My efm-dealer buddy has arthritis and couldn't hang the baffle in a customer's boiler. Although Rich at efm always said that the DF520s all had square-door boilers, this was an original installation from '79 and it had the oil gun hanging on the side of the DF520 boiler with a small round door (AP520) on front. It also had the large, painted, front door on a hinge that covered the entire front of the unit. It was in mint condition.
Getting back to the baffle. There must have been home-made jigs to get these hung up. I could only get one arm in the small door and it was fully extended. Then with one hand on the baffle, I lifted it up and tried to imagine where the hooks were inside. It took several tries to get it in place. I'm sure the dealers were happy when the door was redesigned.