Thanks Chris,
Of all the substrates out there I have yet to try the Wallis paper.I like a deep background color to work on and I have not yet come up with a paint that will work to my satisfaction on Wallis without rubbing off. I have a heavy hand so any standard watercolor, to my knowledge, will rub off. I have a medium in mind but I have as yet not tried it.
For my pastel drawings I use large sheets of pigmented paper, as big as I can get.
Art Spectrum has a premixed tinted primer that can be put on almost anything. Also as I have mentioned before New York Central Art
www.nycentralart.com has beautiful pastel papers, with pigmented grounds, similar to the Wallis surface, in two sizes.
www.dakotapastel.com offers Art Spectrum papers and boards, also in two sizes. They are already covered with the Art Spectrum ground.
I like putting on my own ground because I can color it any way I want it and I have more control of the surface. I can make it smoother in one area or rougher in another.
Hope this helps.