I've been coating watercolor paper with Liquid Light, and use paper safes, and empty 50 sheet paper boxes for drying. The paper has a tendency to rise while drying, and stick to the box top, so I use Sticky-Tack, or Blu-Tack under the central portions of the paper, and painters blue tape on the edges. The Blu-Tack is easily removed after the paper dries, and can be reused. I tape/tack the paper in the light, prior to coating. I've never done cyanotypes, so I'm not sure if this applies, but it's working for Liquid Light.