Thanks. I've been reading a little more about them and it seems like most people who use them like this are installing the carseat once and putting the baby in and out under the belt each time, which is pretty much the opposite of what I would need to do. I need to be able to install the seat with the baby in it every time.
I drive a Ford Explorer with two captains seats in the second row and two seats in the 3rd row. The second row has latch, the 3rd row does not, only the top/back tether. Right now I have my almost 6 year old DD FF in a 5pt in the 2nd row passenger seat. She needs to stay in that seat location due to kindergarten pickup, they put the kids in their seat at pickup time. However, she will be moving to a high back booster before the baby comes. I have a 3.5 y/o DS in a FF 5pt as well, right now he is behind me in the 2nd row. I am thinking the best situation is me moving him to the 3rd row drivers side, and putting the baby directly behind me. However, because I will need to help him in getting him buckled and unbuckled I need to be able to fold that 2nd row seat forward every time we get in the car, which I wouldn't be able to do with a infant base there. So I'm thinking I want to put the baby in her seat, then strap her into the car after I've buckled him in every time. So I either need to learn how to install a baseless infant seat, or figure out a different configuration for the kids.
A new car is not an option at the moment. However we will probably buy something that we can fit the 3 across in the second row within the next 6-12 months (probably closer to 6) so this is hopefully a temporary problem.
Any more advice?? If I could figure out a better configuration I would rather use a base, I just cant figure it out! My DD's seat will be easy to move around but I don't think I can move her to the 3rd row due the the kindergarten pickup situation...otherwise I don't think she would mind having to climb over a seat to get there (although even then it would have to be DS because she couldn't get past the installed bucket seat).