I think trying it out for a while is a good idea. I know for myhself, I couldn't cope, I need my sleep and DH and I do need our evenings together. But you might be fine. We're all different. Try and fit in some time on the weekends after the kids have gone to bed, for you and DH to have some couple time so you don't lose touch with each other.
I remember when I was still in Sydney, I had neighbours who did this shift thing. The husband worked nights and spent the day with their son, while the wife worked days (about 5 or 6 hours a day). The arrangement worked really well for them. No idea how they did it, but it was a sacrifice they were willing to make so they could afford buying a home without putting their son into day care.

Good luck!

Sasa