I see the issue. Interestingly, SL fast bowlers never really looked out of place at their arrival at international stage. Sure guys like Tikshila and Shehan Fernando raise your eyebrows but they are all rounders. I never played with SG, but I play with Kookaburra Regulation and that is the 2nd tier below Kookaburra Turf that is used in international. I did play in lower divisions with various other balls and nothing comes close to Kookaburra. Kookraburra actually maintains very good grip for spinners and doesn't become deformed easly compared to other balls.
Lets see how arm rollers in the name of "Spin bowling" do this season lol
Lets see how arm rollers in the name of "Spin bowling" do this season lol