From: Houston, TX - USA
Welcome to the labor of love that is modding. I dont think a saved game will do you much good. You are doing a midpoint-forward mod. What you really need most is a comprehensive knowedge base for the locations, strengths, and dispositions of the major units on may 1, 1942. The designers already have done the heavy lifting on the OOB. Any changes you may want to make on the oob likely will be minimal. You can use the overall scenario 1 OOB as a shell. You will be modifying most of the units that arrived prior to May 1 in some way. That much is very stratightforward in the editor. Your sources will be all the usual suspects, but please do keep in mind that most of the base forces are game construct units that actually were amalgamations of many other actual historical units. You will need to use a bit of judgement placing these.
Good luck admiral...and I agree with misconduct, modding a scenario such as this is a major undertaking with hundreds of hours of reaerch, execution, and testing included.