I just read this thread this morning. I guess I missed it due to being hospitalized and in rehab during the time it ran. The last couple posts brought it back to the top, fortunately, and I thoroughly enjoyed it over my first cup of java. Thanks to all who posted pics and information. Your Parker try gun is in great condition, Bill.
Gene, having been fitted once with the use of a try gun I cannot say that gun fittings are a marketing ploy. I think they have usefulness, and the try gun speeds up the process immeasurably. As I have mentioned in a previous thread my first fitting was done by myself, with tape, cardboard and an adjustable buttplate. The resulting dimensions were almost exactly the same as the results from the try gun fitting. So, it can be done by someone's self if willing to shoot at a grease plate enough to make the proper adjustments. That said, it is very easy to spend an hour with a good gunfitter and get the exact measurements you need. I completely agree that the consistent, proper gun mount is the key. If you don't develop that before going for the fitting it will be largely a waste of time and money, IMO, and in the opinion of the gun fitter I used.
BTW, as I recall, the try gun he used was an O/U. He told me that the measurements for it would be minutely different, in a couple places, than those for a S X S. I probably have the card he gave me with the dimensions that he wrote on it, and I can't remember if he wrote what would be changed for a S X S, or not.