One reason most folks prefer a 9" sanding disc is you can use any regular sheets of abrasive paper you want. 10" requires pre-made discs.
Most of the abrasive companies carry regular and PSA discs in any size you want. Check Tru-grit, Hermes, Klingspor, etc.
I don't know what you are doing with your discs, but Rhynowet should last longer than a few minutes?