Thank you Hobbes and knp; that was exactly the info I was looking for! I have been searching for a concise list of unit comparisons between versions and couldn’t find anything. I guess my Google foo isn’t as good as I thought it was. And thank you gtsg for directing me to the anniversary map! There’s so much information under the A&A umbrella that it can be a little tedious for a newcomer like me to sort it all out.
Cheers to you all!
Side note: I found a listing on eBay yesterday for some sculpts from 1941 for $10. I jumped at the opportunity. As far as I can tell these should be OK with Spring '42.