Too bad we don't live and shoot closer to each other. I've been having problems with my neck and my "off" shoulder. I finally took the MC off my Browning Trap Spe. and replaced it with a skeet/field stock. Now I don't have to twist my neck all up, and my POI has dropped down to about 60/40. As compared to 110/-10 with the MC stock. Last week I shot a 97 from the 16 yard line & finished 3rd (first time out with the new stock).
Don't cut your skeet stock, but look for a good used replacement stock (eBay) and have it cut. I believe your 30" barrel will be fine for trap.
I shoot the same load for everthing, 1oz. of #8 over a MEC #27 (17.0grs.) of 700X. I had a friend that put a 20 ga. tube in his BT-99, and it really didn't affect his scores at all.
Just keep your head down and keep your swing going