I only had three kid to contend with in my car and used the unity capsule, dd stayed in till 21 months and 10.5kg and about 80cm. She only game out because she is an escape artist and figured out she could hold her shoulders in and get leverage with her feet to push herself out of the harness.

I had her behind driver, middle seat was for my 7yr old no child seat and my 5yr old in her maxirider. The base is quiet easy for people to climb over.

I brought it for my last and absolutey loved it. Especially for school drop off and pick up.

Hope this helps.