Hi Michael, I'm just starting to work with thin papers, so I'm wondering what you have figured out. Do you prestretch the paper the way watercolorists do? I'm having problems with it wrinkling during coating, which has the sensitizer sitting in little puddles, and then it does not go back flat which makes for wrinkles under the neg. in the vacuum frame. I've been hanging the paper under slight tension to coat, which seems to help, but any ideas would be welcome. I'm also trying glued-on edging pieces and corner reinforcements to help with handling in the processing stage, which are then cut off once the print is dry.
Re coating on fixed s/g paper, I read that gelatine and Pt don't play well, but Pd is ok. I've tried Photoformulary's baryta paper and it did not work at all well. That's all I know on that...
Best, Ben