Gun fitting for me would be an exercise if futility for the fact that I shoot more than fifteen different guns at present. And I almost always shoot low gun... sometimes pre-mounted at trap. I'm not a serious competitive shooter but I do like to break a lot of clays when I go to a shoot. I'll usually bring a minimum of four different guns to shoot - different gauges, different dimensions, different barrel lengths, and different weights. I simply re-teach myself how I must mount each different gun I shoot. None of mine are newer than 1935 and some as old as 1880. The thing that is hardest for me to get used to is a LOP that is too short, say 13 3/4" or less....
But I do break some clays and I do have a lot of fun and I sometimes even surprise myself, both in a good way and sometimes in a not so good way.

Most of you are in the position of the 'serious shooter' and that's a good thing... it gives us casual shooters something to strive for.

Having all of my guns altered to fit me would probably break the bank.