| I've got Daytona grips on my multi and they work fine, the switch is easily placed using silicon adhesive as glue, grips go over throttle but not easily and will not go right to the iner edge as the oem grp slips over a raised part on throttle lever. i stuck them down with hondas grip glue and they never move.
multi has an extra socket located inside right hand headstock area, you can buy plugs to fit easily from RS or vehicle wiring products, not sure if ST has this but it might be worth checking a wiring diagram. | 
Threaded Mode