Well, to be honest, all gambit moves really depend on how round 1 (especially Russia 1) went.
If Russia tried for the hat trick (Belarus, W. Russia and Ukraine) and got stomped big time, then the all tank gambit might be the way to go.
If the allies put up zero resistance to German attacks, and you are like me and routinely purchase a bomber on Germany 1 anyway, the SBR campaign gambit might work
If your opponent is cocky, ahem, and there are a few on these boards, the Canadian Shield gambit might work.
Really, the game is turning into reading your opponent and luck and less into strategy for me now. That’s why this is my year of really weird things. Like against Uffish in my league game, I have purchased Artillery, 4 Armor with Russia on Russia 1. (I was going to get 2 fighters and an artillery, but the calculators said I would lose Caucasus. my other idea was abandoning Caucasus and going with 3 submarines in SZ 16 or 2 destroyers or something, just to REALLY screw with his head!)