Bruce, i thought I'd jump in here. I've had a Waco .60 for a year now and it's really a nice flying biplane!! Mine has an OS 91fs in it and has plenty of power. I'm turning an APC 15/6 prop. It may be just a bit much for a 91fs but it flys real nice with that prop. Your Saito 100 should handle that size prop real well. Larger prop looks better with the big cowl. I mounted the engine at a 45 degree from vertical to get the muffler out the bottom.

I also got new bolts,washers and locking nuts for the wing struts from Ace hardware. I leave the wings on all the time so I don't have to assemble it at the field. Just put in the back of the truck to get it there.

Good luck and hope you enjoy the Waco!