Car seat for reflux

Our LO just got diagnosed with GERD. He hates his car seat and screams while in it. He also spits up every time I put him in it, regardless of how long it has been since he ate. I've read that the bucket/scoop shape of the infant car seats cause pressure on the stomach, because of the position in which it causes them to sit (he hates it even when not strapped in). Has anyone with a reflux baby had success switching to a convertible seat? If so, which one?