So the Soviet island has also been quickly mapped out. I went with airfield and letting nooks be bought from it, that way if nooks still turn out to be a bad idea in general then it's easy to drop the map back to "vanilla" behaviour where chinooks aren't available to Allies because they're Allies and aren't available to Soviets because no helipad. There's also the as-of-yet unseen snow airfield. Maybe we should get a snow missile silo too.
Why Tesla coils? Because Gunboats can't handle them. Attack subs can't handle pillboxes because they can't hit land targets at all, so I guess it's only fair that the Soviet base defenses should be something Gunboats can't handle even in small groups (though 6 gunboats could probably down a coil). Destroyers still outrange them as usual.
It shouldn't take much time to get this to testable levels and take a slight variation on what Raap suggested - deleting the original islands from the map, plopping these down on it (except not in the same positions because there's meant to be a shorter distance) so that the original underwater space can be retained, and axing the bigger bergs.
(And if Raap sees this, yes, I know I forgot to tick valpha on some things, and the AA gun platforms are temporary and will become rocks later to continue the original island themes you laid out )