Maybe two ten mm's.
We were just talking the other day about fileing down the welds on intake to allow button head replacement bolts fit down all the way. Locktite every thing you replace , after your sure of fit!
Of you want a quick project, find a kids bike with one inch tubeing and cut the guts out of it with hacksaw, pull crank off makes great motor stand . I welded mine together but were theres a will...
Just strap it down when working