FWIW, I was able to make quick work of the other 7 cans. What I found was that using a shaft sized ~2' channel lock was the ticket. I was able to lock on to the flange nearest the housing base and spin them off in place with a fairly light amount of effort.

In my case there was a very slight amount of rust in the cans and they weren't in bad shape. Interestingly enough the down hanging cans had a very different design than the upside down cans.