In answer to your odds question Grasshopper - using dskelly’s simulator, and assuming a Brit Battleship, Cruiser, 2 Destroyers, and 3 Fighters - around 4% chance to win. A bad idea to attack you!
If you brought the 4th Fighter from Gibraltar and bought a UK1 Carrier to land it on (an awful idea), it increases the odds to about 14%.
Your fleet is locked down without the Destroyer.
Your 5 Sub purchase, by the way, locks your fleet down just as much, but doesn’t provide you the same flexibility vs Britain. No extra transports, and less versatlity with your aircraft.
W Bill - great point about subs and airpower - esp the second bomber. IMO, at some point a 2 bomber Germany is a must.