I can report one of my favorite and more difficult papers to print on now is predictable, easy coating and a great black. Rives BFK a paper from the printmaking world as opposed to the watercolor world. I have only experimented with the 175 gsm but I have some 300 gsm coming in. But very happy that as far I can see at this point it will probably jump to the start of preferred papers for Pt/Pd. This was from using the 20/20 10% sulfamic technique. Thank you for sharing your testing.