Anyone do a successful RF'ing car seat install in the Prius v and if so, what convertible seat did y

Anyone do a successful RF'ing car seat install in the Prius v and if so, what convertible seat did you install? Did you encounter problems with the plastic hinge between the seats (that allows for the recline of the seat bank)? See my problem below, thanks!

Just got a Prius v and love it except now that we're switching DS2 from his Graco Snugride infant seat to a convertible car seat, rear-facing ("RF'ing"), I'm finding a HUGE problem installing it.

The seat I'm trying to rear-face install is a Safety First Complete Air ("CA") that my older DS used. He, of course, sat forward facing ("FF'ing") in it at the time we bought the Prius v, so it installed just fine. Same with the Britax Frontier 85 harness-to-booster seat we just purchased for him now - fine as it's a FF'ing install.

So, trying to RF the CA is a nightmare because the Prius v has these plastic hinges between each of the 3 back seats -- the CA keeps getting pulled tight against the back of the seat, as it should, but then the seat hits up against the plastic hinge and it's just slippery and won't get a good install. Putting a towel or something underneath doesn't secure it, nor does putting the towel over the hinge (even though technically that would not be a proper install, so that's kind of a moot point, but we tried it just to see).

Here's a pic of the plastic hinge:


The CA was narrow in back, so FF'ing install did not pose a problem, but the width of the base of the seat when you try to RF install it is just too wide. We measured the space of the seat between the plastic hinges and you get about 12.5 inches. I think I need a convertible seat that has a narrow platform base -- perhaps a Graco MyRide or Britax Marathon (or maybe even Boulevard)? (Also, DS2 is too young to FF, so that is not an option.)

Ultimately -- I just can't believe Toyota did something this dunderheaded -- it's supposed to be a FAMILY vehicle, but doesn't easily accomodate for the youngest members of the family, IMO!