I just got two radians. I'm thrilled with the ff one, was an easy install, is in tight. The rf one is tight at the base but seems to wiggle more at the top. From what I'm reading, this is okay, right? I can't get into a car seat clinic for a while unless Divy wants to visit , there's none offered til spring according to the police/fire people. But a bit of movement at the top rf is okay?

The place you want to check for tightness is at the belt path. If you have less than 1" of movement side to side and back and forth at the belt path, you are ok.

However, the Radian can be tethered rearfacing. Follow the manual instructions and use the D-ring, tether that sucker and it will not move