Both are fine ideas. Germany will often stack E Poland without the tanks. The total numbers of Russian troops on Moscow is going to be lower whenever you G1, they buy premium units, or Russia tries counterattacks. All of these weaken the final siege, but its typically a losing battle anyway.
You make a good point about Leningrad. Germany really only has 1 money direction to go, in any event (east). Still, the money $$ amounts for both Germany and Japan seem a bit abusive when they exceed what the USA can rational do (75-80). The goal balance wise is to pit a raging america that may have lost its first wave against a germany who has lost the better part of that ground army, but also likely has a big airforce, a big payday in hand, India, Moscow, etc. That late game is dynamic and pretty fun. 53 German tanks, 14 bombers, 12 other planes vs about 40 junk UK units isnt…its a blowout on VCs