I'm having a baby in May and I'm trying to figure out how to get 3 seats across in my 2010 Mazda CX-9. The baby will have a Chicco Keyfit 30, my 22 month old has a RF Britax Boulevard click tight and I was looking to get a booster for my 4 year old. Any opinions on a booster seat that I can put in the center and still have enough room for my 4 year old to buckle herself in. I tired fitting a Britax parkways SGL in the center but it's impossible for her to buckle and unbuckle.