My girls were a little intimidated by the big seats so we started them in the little ones.
My biggest thing with having a little potty was you could see if they went or not and how much. That way you could kind of time when you were going to stick them on there again. Once they were on the big potty you didn't really know how much was coming out but by then they were trained more and it wasn't so important because they could hold it for an hour or so.
I'm going to go post a p/t thread right now with what I did to give you girls some ideas.