Re: G1 Baltic AC buy:
Allies never have to destroy Baltic fleet. As long as it lives, Germany maintains a logistic advantage for the W Eur-Germany-Karelia-Norway circle, and an invasion threat to London. But if the Allies are so minded, UK can build northwest of UK on UK2 after a minimal ground buy protecting London from a G2 invasion. From there, the fleet drops straight to Karelia. If German navy pokes its head out of the Baltic, the UK fleet plus air smashes it. The AC is a continuing problem because it disrupts UK fleet reinforcements (UK will have to retreat its navy for an entire turn to sea zone northwest of London), but that’s not too awful, considering that Germany can only drop 2 units in the Baltic circle, while UK can drop 8 to Karelia/Archangel.
As far as using the G1 Baltic AC to buy time - it DOES work, of course - but by “work”, I don’t mean I think it a superior or better strategy I only mean that the AC does effectively stall the Allies a bit in the Atlantic to some degree. Whether those IPCs would be better spent elsewhere is another matter.
Personally, I’m of the opinion that a Baltic AC is a dead end to a UK1 2-3 fighter build, and that if Germany does build navy, it should be subs in the Mediterranean, and then only when Germany’s already achieved dominance in Africa, and US looks like it may be thinking about landing at Algeria. A German Med AC is not horribly impractical, but I would prefer to use Japanese units if at all possible. (it often is NOT against veteran players).