I have been shooting trap for about 10 years. Thumbhole stocks are not uncommon. I have shot trap with an 870 that had a thumbhole stock and I liked it very much. If the stock fits you, and especially if the stock allows your eye to look right down the barrel, you might give the stock a try. I am not sure but possibly it's the case that thumbhole stocks were more common 20 years ago than they are now. If that is true then it's no doubt also true that the reason for the change is that 20 years ago many more trap shooters shot pumps and autos than now. Many trophies have been won with pumps and autos of course.