[ROL]

I use Arista EDU RC for proofing. It's the cheapest I can find, and way good enough for proofs. I get the big box.

I have a couple of big 250 sheet boxes of Ilford Multigrade RC, obtained from a going out of (the analog) business/moving sale (the now defunct Calypso Imaging) that I only use for contacting roll films. Some call those proofs, but in any case my supply will probably last 20 more years at the rate I shoot and process 120. I only proof on fiber, the cheapest and most easily obtainable of which, for me, is 8X10 Slavich Unibrom – Gr. 3. Proofing allows me to determine the fine art potential of any negative, 35mm through LF. Since part of that decision making process of making fine prints on fiber papers requires seeing it on a fiber paper, proofing on fiber eliminates one step in the darkroom. But then that's my workflow.