For the past couple days I have been coating (and coating and coating) Arches Platine with cyanotype emulsion. Mark Nelson had said that Christina Z. Anderson (I think) used Arches Platine successfully with cyanotype. This in response to my frustrations with emulsion runoff in the washout with first Crane's Platinotype (which seems to be no longer manufactured, replaced by their cover stock?), then Bergger COT 320 (my preferred paper for palladium prints), and later Crane's Weston Diploma (which also appears to be missing in action now?). I'm making much better progress with classic cyanotype on Arches Platine - runoff is minimal and there is no bleeding into highlights.
Platine is luxurious. Have you ever stayed in a high end hotel, hit the bed after a long day of travelling, and felt enveloped by a soft but firm bed, and pillows that invited dreaming? I always wondered where they got those beds. Arches is a thick, 100% cotton paper (310 gsm) that comes in 22" x 30" sheets, with a smooth hot pressed surface, and a neutral pH. It is also available in 30" x 44" sheets. It has no whiteners or brighteners, yet appears very white. The front of the paper (watermark right reading) is smoother than the back and is the side I coat. You can tell the smooth front side of the paper from the rougher back side by light touch (with clean hands) - try flipping a paper over and over and see if you can tell the difference. Not as pronounced as Bergger COT-320, which I orient correctly for coating by touch without thinking anymore. I have been easily rod coating Arches Platine, and the well-sized surface is rugged and does not raise a nap or roughen after repeated passes.
I tear the paper along the edge of a plate glass top I work on, moving my hands down as I tear about 6 inch sections. This gives the resulting sheet a more natural edge better matching the original edges of the full sheet of paper. I've started wearing nitrile gloves while handling the paper to keep from marring the paper with fingerprints which can interfere with coating.