Hi, am look to swap the grip shift controls for trigger controls on my sons Giant XTC 20" Jr1. It has a Acera rear mech, Tourney front mech (7sp shimano with 2 up front which is prowheel eek.) with the Revoshift controls all shimano. Looking online its a bit confusing with different makes Sram/Shimano etc. I can see 7 sp trigger shifters but not 2sp for the front mech unless its a diffent make like Sram can can someone help please. What should i do get new mechs and levers plus sprocket maybe even chain set or can i just get away with some parts ( can get 8sp on back so i am told).