Why not do the following -- get some ortho sheet film - still readily available. Make an enlargement from your 35mm neg onto the ortho film, develop in Dektol for a few minutes, and then either use that or then contact expose onto another sheet to get a negative -- also developed in Dektol. THEN make a contact print cyanotype. Not only is this simple, it is also repeatable and not some kludge. You guys seem to want to find the hardest way to do something at times. Don't bother with a paper negative. You'll want as much UV coming through as possible. You will get great results using film. Of course, you'll have to experiment a bit to get the right exposure onto the ortho film, but actually using the Kodak print exposure overlay will work fine. Remember the engineering mantra --- KISS - Keep IT Simple, Stupid.