Hello, I'm trying to restore a 1980s Dawes Galaxy mixte for my daughter. It has a Suntour Cyclone Mk 2 rear mech and six speed Suntour freewheel. The question is - can I replace the friction shifters with indexed gears? I have seen some 6 speed Suntour Accushift shifters on ebay, and a couple of Shimano types but not sure if they will work! Thanks.