Grains jars with shotgun fruiting chamber?

The last couple times I tried to show friends how to grow monotubs it got contaminated.

This time thinking of trying to fruit grain jars in a shotgun fruiting chamber (similar to PF-Tek, but we have a pressure cooker, so might as well make grain jars instead of pf-tek jars?).

Is there anything special to think about with fruiting grain jars in an sgfc? I imagine just taking the lid off the jars and seeing if they fruit on top? or maybe trying to get them out of the jar, but not sure how this will go…