I honestly beleive Sealion on G3 is still plausible.
Your looking at ~24 INF (depending on how succesfull SBR was on G2)
1 mech
~6fighters (depeding on whether or not he scrambles to defend seazones or incoming SBRs)
1 tac bomber
5 AA guns
vs
13 INF
5 arty
8 tanks (you could position differently on G2 and send more tanks and less arty but it really shouldnt change anything)
~4 tacs (depending on how many you lost to SBRs)
~3 fighters (depending how many were lost in attacking SZ 111 and if any are lost during SBRs)
~2 bombers (depending if you lost any to SBR
Plug those into a battlecalc…Saying that he never scrambled his fighters, you lost 2 fighters in attacking SZ 111 and one tac during SBR.
72% win for Germany on 10000 sims.
Now obviously battlecalc doesnt count for using AA guns as fodder. (id say its closer to 67% win for Germany which is a risk/ with great reward)
but really it depends on whether or not he scrambles fighters to defend seazones and or SBRs
and how succesfull SBR was on london IC.
Ideally he should never scramble to save his fighters for defense of sealion.
If you are using R&D and UK gets Radar then forget it lol