Arches Platine double or single coat
yes it's tough to print in that low a humidity. You should probably build a humidity chamber to get the paper to at least 50% humidity.
You might also add some water to your solution to help coat.
I think using a coating rod or tube first then a soft non absorbent blending brush would help. Experiment with different amounts of drying time. But I think just get it to the point of looking dry and then expose.
You might also humidify the paper again before developing, you should start to get a strong image before you develop.
I hope this helps.