Can someone please refresh my memory on using an older radian 100 with super latch. Can I use latch regardless of my child's weight or do I need to use the seat belt once my child reaches 48lbs or a combined weight of 65? If it matters, it is in a 2008 (or so) chevy silverado crew cab truck. Also, can I use any harness slot for rear facing or just the bottom slanted set? The child in it today is about 20lbs on second to highest slanted slot installed with latch, but I also want to use it for my 32lb+-, long torso kid. Anything else I need to know or that has changed in the manual? I haven't read it in a while and I do not use the seat that often.