Thinnest infant car sear?

What type of car? and what are the other two car seats? You are right about Baby Trend. We never used an infant seat. At one time had two RFing, the baby in a Cosco Scenera where it only fit in the middle, the 3 yr old in the Evenflo Tribute behind driver, and one in a Montery booster on passenger side (for school drop-off). These were the 'best fit' for that car. What works in one car, doesn't work in another! Measure your hip room in the back seat, and then determine your seats width for each. Even then, you might not get the baby in the middle. Fitting three across is like fitting a puzzle together, just without a 'cheat pix'!