Hi!
I have a MVVS 25cc glow engine (1.50) in a SIG CAP 231 EX (ARF airplane), predecessor to the MVVS 1.60 and best prop for this 185cm span, 5kg airplane is definitely a 18x6 Menz wooden prop.
This older version is an ABC engine and develops the same power as the new MVVS 26cc engine. I run 15% all synthetic oil (Motul "Micro" ) and 5% nitro and performance is good but not exceptional, It hovers at 3/4 throttle so a little more power would be nice, but still it accelerates straight up indefinitely.
A 16x10 or 16x12 prop is definitely wrong size if you have the same type of airplane I have, but might be good if you intend to have it in a lighter F3A type of airplane.

I use a 500cc Tettra "Bubble less" fueltank, but the original 500cc tank worked good too. No pump is needed if you mount the tank close to the firewall, this despite that I use the MVVS butterfly carb which has a big 13mm intake. I also use the steel silencer which gives a very muffled sound.This silencer is modified so that a second 11mm steel tubing is welded to to it to get rid if the exhaust gasses and not build up excessive pressure. Best glowplug for my set-up is a Enya 3plug. I never changed the plug in 3 years time and never had the engine stop on me. Idle is around 1800rpm.

Airplane is now for sale!

Regards!
Jan K
Sweden