Wife and I currently calve out around 150 every year, plus we still have a few sheep coming in at that time.   We do the ewes starting in Feb. and the cows start around April 5.   I wouldn't go to a split season thing, to me it seems like twice as much work.   If you have good mothers, they're still work, but a good mom still makes things go easier.

I should add that I've also got an off farm job, working a couple days a week at the Post Office and trying to get ready for spring planting at the same time.   Everything seems to get done somehow.