I would use only one if I could find one I like that is thick enough. For a while I put two in one pillow case but the result was too oval in side profile.
Maybe some of those foam chunk pillows with adjustable loft. Basically the case has a zipper in it and you can move fill from one to another.
I bought a pair of these and some waterproof zip cases and ended up with 3 pillows I like instead of 2 because they both needed to lose about a third of their volume to be right for me.
I would use only one if I could find one I like that is thick enough. For a while I put two in one pillow case but the result was too oval in side profile.
Maybe some of those foam chunk pillows with adjustable loft. Basically the case has a zipper in it and you can move fill from one to another.
I bought a pair of these and some waterproof zip cases and ended up with 3 pillows I like instead of 2 because they both needed to lose about a third of their volume to be right for me.