What about airbase on Normandy/Holland
Not sure about it but I’m saying that I think that spending enough for protection of the Kriegsmarine (in general) may just be inviting Russia deeper into the Fatherland, regardless of the interesting differences between defending with an additional 2AB or 2CV or even going 1 of each?
All strategy for both sides is indeed largely hypothetical, since a large part of the game (for both sides) is more dynamic than a fixed strategy can cover for: action and reaction dominate the field! That is so educational about the forums: strategies being discussed assume a certain action already. Discussing the (possible) reactions to the assumed actions is what makes it so interesting.
Having said that, Axis are largely the side that plays a certain action. The allies then need to come with a proper reaction. And even that is a lot harder than it looks.