You can’t possibly attack Rus with Japan in 4 rounds… If you have optimal results with the axis it still takes you 3 turns to get to novo! You can’t bring enough inf to think of taking Rus on round 4…
For your plan to buy airforce or ships with germany, its doomed… Russia walks over Germany with ease, because the UK will keep wiping out German ships, then the US keeps dropping inf in Eur… => Game over!
For your other question about going 2 trans 3 inf as initial buy for Jap:
You need cannon fodder and inf provide just that. You can’t take Russia with just tanks… Give a mathematical example here. 2 tanks take out one inf, 3 inf take out one tank on def => Russia spends 9, Japan 10. So you gonna lose a lot of value with just buying tanks.
I think a bid of 12-15 was enough for RR. Because you don’t lose ukr and Manch on round one, so 12-15 is sufficient…
My optimal Ger 1 move with RR (no bid) would be:
Lab sz: tran vs fig (WEu)
UK sz: 2 trans, bb and a sub vs 4 fig and a sub
Gib sz: BB vs 1 sub and bomb
Jor sz: sub vs tran and bb
Egypte: 1 inf and 1 arm vs 3 inf and 1 arm.
Then pray you only lose 1 fig, its the best you can hope for…