I also seem to remember something about using LARGE (5/32" ID) vs. the regular size (1.8" ID) fuel tubing for all of the fuel lines from tank pickup to the inflight needle when using the OS 91. Then regular sized from the inflight to the carb. Thoughts anyone?

I run an OS .77 in my Byron F-16 and works fine with regular sized tubing thruoughout and a 24oz tank with 8 oz header.

Definitely get an inflight mixture valve. After one crash taking off too rich, I installed one and it has saved my plane numerous times. I keep it slightly lean on takeoff and richen it out in flight until I see a nice smoke trail.