[Stubby79]

not my area of expertise, but I would assume you'd just put the carb - possibly a bigger one - before the turbo and rejet to get the mixture correct.

I've seen such setups before, though don't ask me if letting an air/fuel mixture run through a hot turbocharger is a good idea or not.

I'd assume running boost on an air-cooled engine wouldn't be the best idea for it's longevity.

Were it me, I'd be attaching a smallish electric motor (like an etek) that I'd only turn on when I needed a boost for overtaking or hill climbing on the highway. Ah, heck, I'd probably try and make it fully hybridized so save gas too.