Today we were given full custody of a neighbor girl(long story).She's been spending weekends with us and will ride in a booster(she needs one). If my DH isn't with us it's no big deal,I just have DD1(15y old) ride in front and 4 other girls all outboard.When we all ride together it's a problem. 3rd row currently is DD3 TBSS passenger side,DD2 Cruz on drivers side. I bought a BB to try center but she doesn't find it comfortable. Without it I find the shoulder belt under her arm. If her mom doesn't straighten up this could be permanent so I need something long term.What seats will work so all 3 can buckle? I loved my old PW without armrests and I know there is a new booster out without armrests but it's pricy and might not even work.If need be I can force DD1 back there since she's skinny but we'll have a fight on our hands and she's tall.