Re: cvt trans
The 50cc atv engine I used has a cvt built in and it performs beautifully. Take off without pedaling and a blistering 50ish mph top end(car speedometer). There aren't many(any) ways to transfer power without any loss, that's just real world physics. I think the cvt's are a great option.
Caution! I give opinions as if they were worth something. Use at your own risk.