I decided to redo the calcs regarding the SZ2/8 battles on G2, trying out different outcomes for losses on G1, and assuming that Germany will buy 1 bomber on G1.
1. SZ2
Russian sub survives G1
Germany: 1 ftr, 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 sub
33.1% win, 66.9% loss
Germany: 2 ftrs, 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 sub
68.5% win, 31.5% loss
Germany: 1 ftr, 2 bmrs, 3 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 sub
63.2% win, 36.8% loss
Russian sub destroyed G1
Germany: 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC
27.3% win, 71.8% loss
Germany: 1 ftr, 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC
58% win, 42% loss
Germany: 1 ftr, 2 bmrs, 3 subs
Allies: 2 ftrs, 2 DDs, 1 AC
81.6% win, 18.4% loss
2. SZ8
Russian sub survives G1
Germany: 2 ftrs, 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 CA, 1 sub
36% win, 64% loss
Germany: 2 ftrs, 2 bmrs, 3 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 CA, 1 sub
60.3% win, 39.7% loss
Germany: 3 ftrs, 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 CA, 1 sub
69.2% win, 30.8% loss
Russian sub destroyed G1
Germany: 1 ftr, 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 CA
26.1% win, 73.9% loss
Germany: 2 ftrs, 2 bmrs, 2 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 CA
60.5% win, 39.5% loss
Germany: 2 ftrs, 2 bmrs, 3 subs
Allies: 2 ftrs, 2 DDs, 1 AC, 1 CA
80.7% win, 19.3% loss