I hope the OS works better than the other gassers we tried .
The basic problem in single cyl engines is an unbalance which is typically stuck at somewhere around 3000rpm

The ignition curve can be tailered to lessen this thump
We tried various motormounts which can help but it all adds up in more weight
If you want to use lighweight Carbon fiber fuselages - the problem can get worse as the lighter the fuselage the more resonance you encounter .
Wood done right soaks up various resonant stuf much better but you also have to fiddle with locations of formers and such to cancel low rpm nodes.
Hope you get a good workable combo- I used Ed Skorepa pipe and we finally threw in the towel as the electric could be built much lighter and power was more constant.