Came across this kinda late. I built a Smoothie, pretty much stock with an LA46 with stock 30-30 muffler.T he venturi was changed to a 1.24in high straight stack and a 0.260 id. Stock needle valve. 10%nitro, 12.5% synthetic, 12.5% Castor. After some fiddling, I ended up with a 11/7 3 blade Master Airscrew.
One minor modification- the kit came with slightly long sticks for the stab leading edge and trailing edge. I like a plane with a "solid feel" so the stab came out a bit oversize, 24in. span, 7.25 root, 4.5in tip = 141 sq.in.
Turned out to a good flying plane with no bad habits.