I recall someone was posting about trying one , but it was years ago and I can't recall the members name..
she hasn't posted for a long time.

you might try a forum search on the name of it, but it might have been posted about back on the BT site...

I always wonder is a set shape will fit me as an individual...

have you tested the general idea with firmly rolled towel?

someone used to let their head hang over the side of their bed for a gravity /traction action.

of course make sure no neck spinal issues before trying those things.