JMO , those double-40 chainrings won't work. The 40t chained to the 34t will raise the gear, not lower it.
Besides, this is a single rear sprocket, so no extra gear to shift.
This is a lot of expensive and work, just to use the 34t moped hub and brakes.
Gypsy needs to tell us what engine he has.
Then we can advise him which sprockets and chainrings to use.
Off the top of my head, Gypsy would have ratios that'd seem like he had a
34t rear single sprocket up to a single 58t rear sprocket.....and no other gear to shift to.
Bad idea.