Interesting thoughts. The odds on a single round SZ111 as I would do it normally (2subs, BB, ftr, tac) are 24% both subs live, a further 39% one sub lives. So yes there is a significant possibility of losing 2subs. If you are really worried you can lose a plane instead. I’ve questioned the merit of hitting the SZ91 cruiser because those subs allow planes to live in SZ110 and SZ111.
Defending SZ112 with a dBat, DD, sub and 3 fighter scramble, the BB survives 54%. I don’t think you can make that attack. If you get lucky in SZ111 and both subs don’t survive but the UK cruiser does, it becomes 87%. And 68% with one sub. All other conceivable scenarios are losers for the UK to attack.
So I’ve demonstrated you need to continue the SZ111 attack into the second round if the Cruiser survives, i.e. germany only hits twice or worse, which is about half the time. In that event you run the risk of taking out the fleet, 38% of the time if one of your subs survived. That’s the biggest risk with this gambit it seems. The chance of both the scrambled fighter and BB living is <6% with one sub but 34% with two subs.
All in all, the chance if the gambit going bad with 1DD bought seems low. Not only does your attack have to go worse than average, their one has to go better than average.
If you did all of what you posted above, I think you’d have to do an attack on Tobruk. Assuming no bid contribution and a German fighter, it’s still 86% for the attackers. Survivors of the attack will likely be taken out by the two units in Libya with air support. Then I2 they will likely be buying a CV which can protect the fleet. I don’t know how this is likely to go but I think you’re relying on the IC to secure Egypt. I certainly see how the IC purchase is on the table if you don’t do Taranto.