Finally came across Edward Cave's 1913 article

Sporting Life, December 5, 1883 “A Walking Shooting Match”
At the great clay pigeon tournament in Chicago next May, match No. 6 for the Ligowsky sweepstakes, entrance $5, double birds, fourth notch, is to be shot under the following novel conditions: Five traps screened to be placed at irregular points in front of the score, which must be placed 30 yards for farthest trap. The trap judge will prepare 13 strips of folded paper, containing each a number from 3 to 15 respectively, from which the shooter will draw one slip, which the judge will privately examine, and allow the puller only to see. The shooter is to walk in a general right line, from the score toward the traps, upon receiving the reply “yes” from the puller to his query “are you ready?” When the shooter is underway the number of steps indicated on the drawn slip, the puller will pull any two traps, one after the other.

The New York Times, August 17, 1884
“Close of the Clay Pigeon Tournament at Metropolitan Park”
The most important event at the clay pigeon tournament in Metropolitan Park yesterday was the Ligowsky clay pigeon field contest, or walking match, as it is familiarly called. This match is shot from 10 traps, which are placed at various angles, four and five yards from each other. Five traps constitute the first and five the second field. Two single birds are sprung from the first field and one single and one double from the second. By a system of drawing lots the number of steps each competitor shall walk, and also the order in which the traps will be sprung, is determined. These, however, are for the puller, as the shooter does not see them until he has scored. When ready, the competitor starts 12 or 14 yards from the traps, and walks toward them. According to the distances drawn the puller springs the traps and the marksmen must fire.
There were 17 entries for yesterday’s match, in which five traps were sprung for each man. Dr. Gerrish and C.M. Stark, of Exeter, N.H., G.T. Tidsbury, of the Massachusetts Rifle Team and Mr. Luther, of Worcester, tied at first, each killing 5 out of 5. On shooting off the tie Dr. Gerrish won by making the same score. Prize, $13.55. W. Zeigler, of the Jersey City Heights team, took second prize by breaking 4 out of 5 pigeons, and C. Wilbur, of the Massachusetts Rifle Team, won third place with 3 out of 5 birds.
There were several sweepstakes and individual matches during the afternoon. A very pretty one was between G.H. Wurm, Gerrish, Dickey, Jenkins, Stark, Luther and Wilbur. Sweepstakes $2, entrance fees all to go to winner. Wurm started off with a straight 7 killed. Stark, however, tied him, while the others made one or two misses and fell out. In shooting off the tie Wurm missed 4 birds and Stark won easily with only 2 misses. Another sweepstakes match at 18 yards resulted in Messrs. Wurm, J. Von Lengerke, and Remington making 7 birds out of a possible 7. They did not shoot off the tie, however, but divided the money. In another match Holden, of Worcester, killed 7 out of a possible 7.
The tournament closed yesterday, and in point of shooting was a success. There was not much public interest taken in it, however, and the gunmen did not have very large appreciative crowds to witness their performances. As many of the sportsmen were compelled to go home, a proposed dinner at Coney Island today was given up.

New York Times, Sept. 1, 1892 “A New Feature Introduced at the Keystone Tournament”
New London, Conn., Aug. 31, 1892. – The tournament of the Standard Keystone Target Company was continued today, with an attendance far beyond expectations. In some of the events the entries ran over forty. Shooters were present from all sections of Connecticut, and a very large contingent from New Jersey and New York is on hand.
There is one new feature connected with this shoot that has not been seen at any previous one. One half of the events are shot under what is known as the novelty rule. Here the targets are thrown from eight traps, expert rules, and from some of the traps targets are thrown as incomers. Heretofore all targets have been thrown away from the shooter. Under the new rule there is considerable amusement and but few straight scores are made.

Edward Grossman, “Field Work at Clay Birds” Outing, Sept. 1912
How to Give the Trapshooting Game a New Flavor of Variety and Excitement
https://digital.la84.org/digital/collection/p17103coll2/id/15354/rec/191

Edward Cave, “Clay Bird Golf”, Country Life in America, September 1913
https://books.google.com/books?id=kIQ3AQAAMAAJ&pg=RA4-PA47&lpg

“The Shotgun As A Means Of Sport - Clay Bird Golf”, Arms and the Man, November 6, 1913
https://books.google.com/books?id=tZgwAQAAMAAJ&pg=PA109&lpg
Mr. Edward Cave, writing in Country Life in America for September, presented what he called “Clay Bird Golf.” He described it as a fascinating new outdoor game which combines the best elements of golf and of shooting. He indicated a way to lay out the course and presented a system of scoring and rules for the game.
Our interest in this subject is such that we shall have more to say about it later on. It may be observed now, the essential principle of it is that one goes from place to place with a companion and fires either at singles or doubles thrown from concealed traps at unexpected moments and with a variety of angles and lines of flight, including overhead birds.
This plan appeals to us very strongly. We know a great many men who have shot for a season at the traps and do so no more. These are for the greater part men of the cities. When asked their reasons they say: “I need exercise, and I really cannot afford to spend money for trap shooting when to get my exercise I have joined a country club where I may play golf or tennis.” There are many such cases.
The cost of a clay bird golf course ought not to be greater than for a proper golf course. Each year, in this country at least, a larger number appreciate golf for its true worth. Men who scorned it for years, as a piffling pursuit, as a pastime of the senile, “the old man's game,” they said, upon trying it found that it is not only a game for the old man but for the young as well. They found that its chiefest merit is that it takes men into the open air and compels them to walk and swing their arms. That means exercise and exercise means more freely flowing blood and health and a greater capacity for work.
We have long held the opinion that some modification of the trap shooting game, which would make it more of a sport, would ultimately be found. We believe the suggestion for “Clay Bird Golf” to be of great value. Not the least benefit to accrue, as every practical reader has already concluded, is that shooting under such conditions will help a man do better field shooting, and that is not always the case with straight work at the ordinary trap.
Of course trap shooting should be continued with all the changes in its rules, which shall seem to those best advised the real improvements calculated to make it a more popular sport. It is a good game, worthy of all support. The more forms it has the better.
We sincerely hope some of the shotgun enthusiasts will quickly take up and energetically carry out sensible plans for making shotgun shooting at artificial targets a better game. We are not too long on earth as it is, and a little real pleasure, such as one gets from a successful reaching for things with a shotgun, adds much to the zest, and likely, to the length of life.