I've been a huge devotee of the Bergger COT320, which seems to be about the most viceless pt/pd paper. You pay accordingly, but there's no need to double-coat or acidify. I think part of your problem is that you're using the backside of the paper. You may not like the pattern of the front, but it is pressed and rolled to give a tighter texture even when wet.
Where are you getting Cot320? No one seems to have it except B&S, and they've been out of stock for some time.