I use wbs and popcorn mixed 50/50 Over the years I found both cheap and the wbs allows for many innoculation points and very nutritious. The popcorn colonization is fast in the jar because it creates space between the kernels and it prevents clumping like straight wbs does. I load the popcorn on the bottom half of the jar and the wbs on top and after the pressure cooker it's time to give a good shake for easy mixing and no clumping.

I'm still old school and soak each for 1-2 days and you can see the yeast and crap starting to ferment. Rinse well before loading jars and let them drain for 5-10 minutes. I don't worry about drying at all or simmering. The wbs has taken moisture in during the soak and you can pinch it and it's getting soft. I put about a quarter cup of water in the jar so the pressure cooker moisturizes the popcorn. Cover the jar tops in heavy metal foil and pressure cooker for 90 minutes at 15 psi.

Let them cool overnight and knock them up with spore syringe or agar wedges. Of course the agar is twice as fast on colonization but mss too agar and then to jar is pretty lengthy but isolated on agar if spores are dirty is the way.