FF carseat for Toyota Tacoma Access Cab?

Hi Everyone,
My husband drives a Toyota Tacoma Access Cab which has fold-down rear seats. The manual clearly states that carseats can be installed in the back on those seats (and there are tethers). But we are struggling to find a FF seat for our 5 year old daughter (36 lbs, 41" tall) that will actually fit.

The problem appears to be the headrests which tip slightly forward. This means that the backs of the car seats I've tried (which are tall enough to overlap the headrest) are pushed too far forward to get enough of the base on the seat (there is a gap of about an inch and a half between the back of the carseat and the back of the seat). The headrests are not removable.

We've tried an Evenflo Maestro and a Diono Radian. Does anyone know of another FF seat that would fit my daughter's size that isn't as tall as those two (something that might come in underneath the headrest so it could be pushed all the way back)? Or could we look into a booster? I'd much prefer she be in a harness, but this would be a sometimes ride, not a regular one because she typically rides in my car (a Prius). It would be so convenient if my husband could pick her up too though, especially as we have a new baby coming next month.

Thanks for any help and ideas.
Rebecca

Something with a no rethread harness might work better. The "shell" tends to be shorter, and the headrest sits further forward, so it might not interfere with the headrest. Graco Tranzitions or Contender?

Thank you so much for these ideas. I will look into those.