When I started palladium printing I found a german drafting paper, Schoeller's Parole which worked perfectly and I could get some old stock (I guess late 70ies or early 80ies). Now that is gone except a very few sheets. It had a very smooth plate surface but also gave good blacks with a smooth tonality of highlights. As I am printing mostly 5x7 a smooth paper which gives high resolution is very desirable (not so much necessary for digital enlarged negatives).

I tried over the years a lot of papers but none came close. Here are my comments about some of the presently available ones:
Arches Platine: Good color, blacks o.k.(some comes off in the developer) but not very smooth mids (some grain) and highlights inconsistent. Surface too fuzzy after processing.
Revere platinum: Good blacks but mid grain and +/- missing highlights. Good paper surface even after processing (clears well). Black spots (paper contamination).
Weston Diploma (recent version): Good blacks and tonal range but wrong color (looks like manila folder) also gets quite soft during processing.
Buxton: Good tonal range and good blacks when tweaking the chemistry. Too much surface structure for small prints. Sporadic black spots and other paper flaws. The best of these.
I also just tried Awagami Masa. Blacks o.k. but good tonal details in mids and highlights. Color bright white with hint of blue/gray. Surface smooth but on the second sheet I tried some paper fibers came off during initial bath in the developer (looked like worms in the sky).

I would appreciate any hints to papers I should investigate. My preference is smooth and white. A lighter weight paper (80-150 gsm) would be great for making hand bound books.