For UK "legal limit power" the 99's stroke seems fine, evert, and many people are pleasantly surprised with its excellent manners. Although many would aim at no more than 10.5 to 10.7 with a .177. Having said that I have shot out of the box .177s doing over 11 very happily and sweetly. When fitting nose extensions to the 95, I think most people go in the region of 8 to 12mm.