Thanks. I actually have one of those as well - it works great for my younger kid. I tested a Graco Granzitions as a high back booster (w/o harness) and it fits OK but definitely needs a seatbelt extender - my older kid won't be able to buckle herself. Just called the dealer for p/n LJ6Z-78611C22-AAI am using the Graco Slimfit 3 in 1 with the latch system on the rear passenger side. I've been using it for almost 2 years in my car and don't have complaints. The cup holder can close so it will allow the driver side back seat and middle seat to fold forward.
https://a.co/d/0g010Hhb
I can provide pictures in the morning if you're interested.