I pumped down the wood for a while, then introduced the MMC. I'm pulling 25" with two stage Gast pump. It's been foaming for an hour. The MMC doesn't cause foam overflow into the collection jar like other agents I've used. I'll let it pump until I can't see any more air bubbles coming out. I hope this is the stuff, because now I've got four liters of it.
It's flammability rating of three makes me nervous, but I'm doing it outside of course, and using a diaghram pump.