That is an interesting modification. Who does that hurt/help the most?
You imply that it would help the allies, perhaps it might, but I believe Russia’s tank purchases are on a comparable level to Germany’s tanks purchases (from percentage of total output perspective).
Another common strategy is to have USA create a tank corp through north Africa, so their tank purchases can be high in volume as well.
Our personal preference to balance the game is to have a bid (pre-game start placed, limited to one unit per territory). This also gives different openings at times for more varied game play.