Mine is a 2-stroke recoil start - as regards strength I am fairly weak even for a girl so your wife should have no problem with the starter
. The only problem with the compression is that sometimes it catches short and that can hurt (at least it hurts me)
All the GEBE rackmounts use recoil start engines although you can retrofit any engine to the mount so long as it uses (in the case of my bike) a 78mm or 52mm clutch. I am toying with extending the recoil so it can be pulled from a position forward of the seat without twisting..
The clutches on the GEBE kits are centrifugal - push and go - and all have a kill switch... BE SURE if you do fit it that it isnt shorting - I had that happen once and I was trying to start the engine for so long I actually bruised my hand (a relic of when my father shut my hand in the bootlid of the old Renault we had...)