Check out
this info, it is really useful and there are some widths of different seats in there. I have been looking at a bit of info, as we will need to downsize to slim line when I eventually have #3,
DD is heavy & tall enough to go into a booster with a H harness, I will probably get her the vario kid,
DS will probably stay in this 5 point harness seat, and I am hoping to get a capsule for the baby.