I would test the Baryta paper with your POP formula. Some POP - Baryta combinations don't work and some work but do not keep well at all.
The paper is not available in small rolls or cut sheets except via the Formulary at this time. Schoeller will not sell this paper except in bulk quantities of many many master rolls per order. Your best bet is to make your own or buy from the Formulary. I know that Bud has a goodly stock of rolls as he stated above. Look for it on their web site.
If you do buy rolls, beware that Baryta paper has a good "set" to it and must be precut and laid (pressed) flat for a few hours before coating due to this curl. A weight on top of 20 - 40 sheets will flatten them all out in a few hours.