Can you explain how you obtained this figure of 70%. From what I can tell, for a G2 sea lion Germany will have at most 5 tactical bombers, 5 fighters, 1 bomber, 1 inf, 1 art, 4 tanks. That’s with a G1 build of 4 transports. Ave. rolling for hits is around 8 - assuming 1 fighter and 1 tac bomber are killed through anti air. Any return fire from uk troops can be allocated to the planes. So, when pressing, Germany will have 1 inf, 1 art, and 4 tanks compared to 5 inf and 5 fighters. I fail to see how Germany has a 70% chance of winning that battle. Or am I missing something?

Germany has 5 Inf and 5 art or tanks and would take the inf/art/tank casulties first except for 1 tank and then figthers and bombers. Attacking round 2 is risky - you will likely lose about 3 fighters and 3 tacs depending how the rolls go and if UK dumps everything they can to defend - but you should win 70% of the time according to every odds calculator I have used. That being said, one thing I neglected to consider is if UK scrambles. To prevent a possible catastrophe, it would be best to keep 1 Fighter with your navy, which would drop your land battle odds down to 60% if they dont scramble, but a sure victory if they do scramble but fail to destroy your transports - keep in mind all you need is a draw.