Stan, I liked the 20 bore double at first sight but when I saw it had 34" barrels I had to give it a go. My bid did not break the bank. I've made more costly mistakes as my wife says.
It should be fun to shoot. I intend to pattern it with a few loads I have come across. Eight shot is fine but I like 7 1/2 or 7's if I can get them. If you are comfortable shooting a .410 with 1/2, 11/16, or 3/4 ounce shot you should be just as comfortable shooting 3/4, 7/8 or 15/16 ounce in a 20. I was going to try to find a nice 7/8 ounce load and see if I can get a decent 20-25 yard pattern out of it.
I have been very good at estimating ranges and sticking within those self imposed limits for years. I have no use for sky busting, by anyone. There is a time and place to take extended range shots, but only under the right conditions. I watched my father take a limit of dove, after he figured out his range limits, due to sight limitations and advanced age. Fifteen dove in about a box of shells, with a 16 Fox I loaned him. It was bang, bird down, pickup bird and repeat almost every time. It gives me hope that if I make it to 90, that I will still be able to shoot with my sons and grandsons.