Re: Radian FF seated height?
The radian is outgrown by weight or when the tips of child's ears go above the shell. Diono allows shoulders over the top harness slots.
The True Fit has lower top harness slots and the seat is outgrown when shoulders go above the top slot.
The radian is pretty close in shoulder height to most of the other FFing harness combo booster seats. Only the Britax Frontier offers any significant growing room off the top of my head if you need to harness longer.
IHA: 1 wool interlock soaker (M/L), 8 lacey bum pocket diapers, 1 Wahmies pocket diapers brand new (OS, pink)