I hear and respond! Wow, what a nifty plane design and build!

The weight and wing area ratio is excellent! You can go with whatever cylinder you want and adjust line length to suit.

The venturi diameter is the real key to performance v/s fuel draw on the reedies. Put on the hottest cylinder and high compression head (extra gaskets may be needed) and start with the 5x3 "rubber duckie" black Cox prop on 40' Spectra lines (lightest available, round, not flat braid).

Handle line spacing about equal to the bellcrank spacing

15% Nitro should be fine, but at least 50% Castor in the fuel. 15/10/10 is a really good fuel for steady performance and long engine life. The Synthetic will keep the engine free of varnish, too!

You are on your own in tuning the mode for even better performance. If the engine is really solid, try the 3 blade prop. Adjust line lenqth to reach a balance of reliable control vs lap time. Nobody can give you the absolute optimum combination but yourself.

My goal is to give you a safe starting combination. But even with that approach the first flights with all due caution.

That is a sweet plane! Very nice!

Thats a nice looking model that I think is about the right size...are you using a separate fuel tank to give enough flight time ??