I too like to press hard on Europe as US vs a J1 DOW, but I’m not yet convinced you can do so for more than 1 1/2 buys. 1dd/2ss/2AC (stealing Pacific planes to fill) into Europe on US1 is usually enough to complete the allied Med domination, depending on G1 and Taranto success. Add another carrier/dd if necessary, otherwise, 100% Pacific navy for the next 6-8 turns. I call this the “Kill Italy First, but also Kill Japan First!” strategy. Patent pending :)
My theory is that US cannot afford to build transports until the late game against a J1 Dow. Your job is to be Death, the Destroyer of Navies: AC/dd/ss/fig only for the first 8-10 turns, and swap in some bombers if Germany really wants a Sealion. Have your allies do the dirty work with land units: submarines for days, baby.