Help picking booster please

[longamkl]

We are in need of a new car seat/booster solution and I don't know where to turn. My almost six-year-old twins are currently in Pinnacle 90's and ride mostly in my 2014 Jetta Sportswagen. However, we are now going to begin carpooling with a 12 year-old who must ride in the back so we need to be able to fit three across the back seat of the Jetta. This is not possible with the giant, heavy Pinnacle 90's. C is 48" and about 52 lbs and E is about 46" and about 47 lbs. We do a half hour drive each way to school and sometimes again for activities. They do sometimes fall asleep on longer drives. We are also going to be renting a car and flying to visit family in Canada in about a month and it would be great to get some boosters that also complied with Canadian regulations and were more travel friendly than the Pinnacle 90's. I don't want to be uninstalling the Pinnacle 90's all the time if I drop off the kids in the drop off line at school so what do people do when a different parent may be picking up the kids 2-3 days per week? I don't understand all the differences between low back booster, high-back booster. Is there a no-back booster? Can you experienced Mammas please point me in the right direction? If it makes sense, I'll Craigslist the Pinnacles and use the proceeds towards new boosters so budget isn't so much a consideration. Thank you!

[Joolsplus2]

How old is C? Maybe you can do a backless (like a Cosco Top Side or Harmony Youth Booster, both super narrow and about $13 at walmart/target) and put the 12 yo in the middle between C and E? Unless the booster fits in the middle, 12 yo window seat/outboard.

Low back booster was an unfortunate name many of us adopted years ago when we meant backless, they are the same. Then you can just toss the Pinnacle back in for C on longer trips.

Unfortunately there's no seat that technically meets both US and CDN requirements (maybe one infant seat does now?), there are slight differences in CDN models (a little more head foam, instructions in French, and a lot of other differences for RF seats, but not really for boosters), but there are models that are so similar you would never get caught using the wrong one (and probably have some kind of tourism immunity, I'd think). Something basic like a Turbo Booster or Big Kid AMP are fine for carpooling and light weight, and I think are in Canada too (the Turbo is there for sure). They can be used highback or backless, and might be narrow enough for fitting three across the third row, but maybe not. Maybe just the skinny backless for C and a highback for E, then...? That would cover the three across and travel.

[longamkl]

Thanks Jools. I'll looks into getting a couple of the Turbo Boosters or Big Kid AMP's and trying to fit them across. C & E are basically 6 now so as much as I would like to keep even one of them in the Pinnacle, I'm not going to get away with putting only one on a backless booster.