1. I dunno. I've never tried it in the cannon. Hmmm.. something new to try! I've used it in a bucket several times, but I always mix stuff in the bucket to have zero foam. Makes it easier to get good flow through the BHB that way.
2. Definitely. It'll make quick work out of old sealant, brake dust, whatever type of nasty is on your wheels, it's gonna take it off. It's not *quite* as major league as an acid based wheel cleaner, but it's still strong.