Hi!
I've been servicing MVVS engine since 1992 and can assure you that MVVS engines do not need any longer running in time than any other modern engine (means no time).

Castor oil isn't needed either. Over here in Europe 15% all synthetic oil is what most of us use. But if you cannot get the oils we use, Motul "micro" and Aerosynt 2 and 3 then ...use at least 20% oil. Whether this is straight synthetic oil or Castor or a mix...doesn't matter.

The MVVS.26 engine with it's big golden top head is supposed to be used for Aircombat competition...but it could of course be used for sport flying too as the engine is just an ordinary sport engine, the only thing being different from the other engines in this series (.21, .25 and .28) is it's big head.

Carb functions as any other R/C carb with metering function. It has got two needles , one for high speed adjusting and one for low speed (idle).

All modern MVVS engines (with blue or golden head) could be run on 0-15% nitro fuel.

A good prop to start with is a 9x5 APC, provided the black mini pipe is used. There is a more quiet silencer made for the engine though for those that require a less noisy engine.

A good glow plug is a Nova Rossi 4 or 5.

Tank size 150cc . Best tank is a Tettra "Bubble less" or second best a ordinary tank set up with "Uni-flow" system (two clunks)