RE: MVVS .49 fuel
RCer,
I did no specifically see that you are from Denmark, or I would not have mentioned these brands.
The MVVS .49 hardly spews any fuel droplets from its carburettor, while running, even when adjusted too rich.
So the 'brown engine syndrome' will not be too much of a problem.
Castrol-M is Castor oil, for all practical purposes.