Success! After a year of crazy-making problems, we think we're there. We may not be perfect, but we are functional. Here are a few things we changed along the way.
We are using the Photographers Formulary New Cyanotype Kit. We ground and mixed the chemicals. It all seems to work. We did have better results adding more citric acid than the few drops the instructions recommend. When we only added a little we got yellow stains.
We tried coating with a glass rod, but we never seemed to get enough emulsion on the paper. Also, we tended to get horizontal stripes where the subtle change in pressure of the rod affected the thickness of the emulsion. Perhaps it's the paper we used. Even though it uses more chemistry, we had better results with a sponge brush. After we decided that we wanted more emulsion, we tried applying one thick coat versus two thin coats. Two thin coats (the nail-polish system, as Jaime calls it) worked better. We allowed the first coat to nearly dry, than added a second layer.
In an effort to avoid blobbage, we started hanging our coated paper with two clothes pins, hoping the slight collecting of chemistry at the bottom would be more even. This resulted in more evenly distributed blobs, albeit slightly diminished. We did a "slidey test" to determine our optimal exposure, that is, determining the time needed to get the maximum darkness in a print. On a sunny day in March, it was five minutes.
All in all, with the exception of a few errant chemistry blobs, our desire for more-even coating and perhaps a bit more curve tweaking, we think we're there.
Of course, because we can never actually arrive at the finish line for even a minute, now we want to learn to tone. Preliminary tests indicate exposing for almost twice as long, bleaching in washing soda and toning in tannic acid can produce some very nice tones.