Question Need help choosing new seat

I need to get a new seat and have looked at so much info I have confused myself. So, here is my situation what would you do?

DS -3.5yr, 36.5” height, 30 lb.-currently in TFP


DD -1 yr 28” height, 24#, currently graco safe seat step 1(expires in DEC)

Want to put DD in TFP b/c of the ARB but need new seat for DS. He has just been turned forward this month so I was looking at a nautilus, prosport, and frontier. I really wanted the frontier. But while checking all three out the Graco is the only one with built in lock-offs. We install both seats in a middle position 2000 suburban with lap belt only. I thought we needed to have the lock-offs for this but I have seen some things about twisting the belt instead( is this really safe?). I also would really love to make this last thru booster mode- as long as possible. That is where I stall about the nautilus. I have read that it is not a great booster but the frontier is. The prosport I read a lot about difficult seat belt installation.

Also, I checked about retro fitting latch(I do have tethers) and found out it is a no go, but they said that GM has a part number for a seat belt kit? The woman didn’t know what it was or how to use it but said it was something to use with the seat belt for carseats that I would put on. Anyone know what they are talking about and if it would help install at all?

First off, good job mama for keeping your ds rear facing for so long :thumbsup: Does your vehicle has lap/shoulder belts outboard? Also, are there headrests?

yes there are lap/shoulder belts in all outboard positions and head rests on all but middle.

Although I really want to keep them both in the middle if possible. That's the reason I bought a suburban instead of something else.