The Hampton is great, but it will definitely not fit the OP if a GPA fits her well. The COs are for a much different shaped head. I have had both brands and the GPA always felt like a vice on my head; the COs are perfect. They are much more oval-shaped than a GPA.
The GR8 and the JR8 aren't oval. All the rest of the CO's are (not talking about skull caps...don't know about them), but the G/JR8's are much more round.