The air entering the crancase comes from a fitting of the throttle body: this air has been measured by the MAF. I don't understand why a different PCV valve diameter or orifice should affect fuel trims.

My catchcan is working for sure because I empty it every 2000 miles (more or less): the content is about 50 ml of oil.

This is the catchcan: the orifice is inside of the inlet fitting on the left. On the right side there is a checkvalve, that hose continues to the fitting in the intake manifold.