it seems we are getting the same transmissions from the mothership
i have been playing with paper negatives and ( hand coated ) lumen prints and my exposures are hugely long in direct bright sunlight ...
soon i will be making in camera paper negatives with hand coated paper negatives on
cold pressed/smooth thin sketch paper and exposing on cyanotype paper. like talbot's paper negative, the writing paper
is thin enough to allow light to pass through. regular photo paper seems too dense/thick.
it seems like a lot of work, but it is pretty easy once you get the coating down, and fresh ( sort of ) emulsion.
i am sure with cyanotype chemistry, writing paper or thin(ish) cold pressed paper will work with your lighting system,
or at least bright direct sun with a long exposure.
have fun !