Thanks OND for the suggestion… The engine is CCW rotation. I would always have the PTO on the same side. Just deciding which direction to point the exhaust and carburetor. Either carburetor forward or rotate the engine and point the carburetor towards the rear of the bike..... if I'm thinking correctly.
I've heard that the Tillys idle much better with the stack down, but they run any which way. You just have to make sure the reed cage ports line up and are flipped commensurately. I appreciate you posting up the detail, (and OND's comments) as it helps me in my build as well.
If you're able to fabricate the exhaust to clear, go for it. :thumbsup: