Grandma here, we only drive kids to or from school or to or from their homes to ours. No long trips so "comfort" isn't as important as safety. No trips longer than 20-30 minutes. We have a Mazda 5, so very small but we needed the 4 seats for one of the families. I am now moving seats around, we need one seat belt (long legged 11 year old), one backless (long legged 9 year old), one HHB (7) and one harness (just turned 5). There is so little leg room for the 2 older kids, how do I find the shortest HHB from front to back? We have a Nautilus and a KidFit for the HHB and harness available, I was hoping there was something less "deep" I can use.