I’ve got a novel solution for you…
G1: Take Paris with all reaching 2 move units, and leave the rest of France alone. Put some air down in SI to try and dissuade an allied attack on the Italian navy.
On I1, take SF with as many units as possible. Try and save as many transports as you can (although this is largely out of your hands).
G2: Use all of those mech units to crush Normandy. Build a few transports, so as to make it look like you have that all in Normandy to set up a Sealion.
By now, hopefully, there is a fairly-sized stack of units in Gibraltar.
I3: Attack Spain with your SF ground and whatever else is necessary (transports with sb, planes, etc.)
G3: I’m sure you’ve guessed it by now… blitz through to Gibraltar.
I have yet to try this in a game for only one reason: Turkey. Sweden going pro-allies is not much of a problem; if anything can reach it, Germany hasn’t done her job.
But what can be done about Turkey? Russia would get 8 free troops, +2 IPCs, AND a bonus!