- Fewer groups of transports needing protection.
This is almost never a problem, by the time the U.S. get’s going, it’s not like you have swaths of German subs and aircraft to get worried about.
And making sure you move every possible unit including your aa guns - as you mentioned is crucial.
In all honesty, why bother with a shuck that does ANYTHING but land in gibraltar? In Gibraltar you can base planes with the Airbase, and have Scramble protection for Free, you are also at a naval base with insta-return home, you threaten an Axis Capital, and threaten 7 traditionally axis held european territories including denmark, excluding rome.
Your naval elements defending your transports are also in strategic positions to strike against any mainstream axis naval movements, particularily Italian fleet, AND! You are always in position to open the Denmark door for the British to make the capital grab of Berlin. Don’t forget, from Gibrlatar you can cancel the Sweden NO, the Morocco/Tunisia etc NO, the clear med NO, and possibly the 3 of GIB/GRE/SFR/EGY NO.
There is no reason to do this differently. Reinventing the wheel here isn’t going to score you an extra INCH!