I know that the large round cowls provide insufficient cooling if the engine is not baffled. This may be against your opinion, but that is how it is. The engine mounted on a test stand will also not be cooled well, and a large open cowl is no better. This is not my opinion, this is my experience after cylinder head temperature measurements.

The added metal salts in mineral semisynthetic oils provide some kind of lapping compound to get a smooth micro-surface, that you can do without. Good synthetic oils have sort of restructuring of the surface high spots without tearing metal parts out. The engines I inspected had a very nice pattern all around the ring, and no wear to speak of. The ring gap increased only 0.1mm after about 80 liters of fuel (~20 gals). his accounts for 0.03mm ring thickness wear, using synthetic oil from day one.
For engines with sloppy finish, this "lapping" may be needed. Not so with the precision finished MVVS engines.