Going early but with less units makes it difficult once the front starts expanding. You lose the early advantage that made the historic Axis success possible.
I've tried this twice and the first time it worked out well, as eventually Russia folded and that frees up a ton of Axis units that can then defeat the UK and US. The second time it didn't work out so well as I never got anywhere in Russia and then it was all I could do to hold off the Allies. For many turns.
End of the second try, which was an Allied Minor Victory:
