Just watched the YouTube video commented but doesnt appear my comment posted ;-S I would DEFINATELY swich out the front rim as well as the rear the front failing your in the lap of the gods and gravity if the rear goes sliding to a halt is an option rather than a swift journey over the bars which 99% of the time ends in broken bones...
Brace the frame definately, bicyle tube is very thin and will break/bend easily with the added weight and stress...Too late now but i would have suggested a 10hp watercooled pocket bike 47cc motor would of gotten better performance due to better power to weight...
Best of luck
KiM
p.s Eno any word on the spare rim and hub buddy? Ill be financial to purchase in lil under two weeks if thats cool with you?