I was JUST thinking the same thing last night. The infant car seat and the two bases are just sitting by the front door. It seems silly for them to be just sitting there when we can actually be working out what works best for my car, and FI's car.
Tentatively, I am thinking this week I am going to adjust the carseats and figure out what works best. I'll probably look a little ridiculous riding around with an infant car seat but, meh, whatever.