all i can tell you is that bill baxter recomended an 18 inch prop for 8000 max, no more
i bought one from someone and they ran 15 percent and leaned it out way too early in the break in process, they also took the baffle out of the muff, dont do it! these engines are not made to put out much more than 7500 rpm, mine has slight scoring , but no ring damage
its a brute of an engine, i need a needle valve and a muff, also it will go in a giant scale plane
which is still in the works, i havent run it yet. there are all kinds of schools of thought on this engine, as far as nitro , alot of people say they need high nitro, but its always better to run rich
even with a high nitro content, the manual states only to use 18 percent oil, no mention of nitro.
the other thing is that the manual says max rpm is 10, 000, ITS WRONG!!!
TANK placement is 10 -15 mm below the carb centerline

let me know what you find out

thanks