you mean using non-random weather. Yes of course. Personally, I prefer random weather as it gives a level of uncertainty and fun, but that's me. And random weather is by nature... very random! So the first turn might not be as hoped for.
And yes, it's true that there are good periods in may beginning of june in which limited progress can be done, but it always has to take into account the mud that's coming, so everything has to be more cautious. By example, in the first turn of the game, you can take risks, push your spearhead very far without too much regards to flanks... but if a mud turn is coming, that is not possible unless you want to get your spearheads pocketed in their turn without hope of immediate relief.
So I really think that gives a big advantage to the Soviets. Of course, how it would go afterwards would still be very interesting!
sorry that I can't help you on the technical side.
"So much trouble in the world!" -Bob