If Germany buys 2 transports, then UK should buy 6 infantry and 1 fighter. Sending all 3 fighters to Taranto is probably overkill esp. because of how badly the mechanics work when all you have left is 2 fig 1 CV (since they just retreat and you die). If you save 1, you have 3, which is plenty to keep fortress UK alive, 2 is also fine.
After you buy this, on G2, you usually get bombed, and again on G3, so in our current game I have 20 damage, 1 armor 1 mech 5 AAA and 13-16 men or something like that? UK is hard to take, though with some money, Germany could re-ramp that threat up–instead he headed to med to do an Africa Gambit. Once you have those 25 or so “2s” on the UK, its not a cakewalk to take anymore, he needs to focus all his effort and money and ships to keep the threat engaged, which wastes his time.
Unless Italy can come in, even a 2-wave Sea Lion doesn’t pull odds against the turtle. If he continues to build up G3+ rather than coming into novogrod by sea or moving to SZ 91 (both places, he can STILL sea lion you from, as well as do other things) then you have to continue to repair and add more turtling.
If Germany sets up for a true, G3 Seelowe, it is just an odds battle and UK has 2 entire buys 61 minus damage to get ready. Even with every plane available, the odds aren’t in his favor—he has to throw everything at you just to kill the AAA then come in and hit with another round of troops on G4, its all his resources, Russia is rampaunt.
The odds are pretty well playtested–if Germany is quite lucky no matter what UK did, he will win, with 1 tank and a few planes alive. But he’s dead long game as USA and USSR demolish him.
On the other hand, the odds are uninviting as UK is doing the optimal response, so he usually has to go to some Plan B (attack Russia by sea or take Gibraltar) which is clearly sub-optimal.