So here’s the lifting rig that finally popped the barrels loose. Torqued it up as tight as I dared (the bed frame angle iron was actually starting to bend slightly, where the all thread picks it up). Poured the heat (paint stripper gun) to the area under each front end stud, where the locating sleeves are. Then a few good whacks upwards with a long brass drift and a 2.5 lbs. hammer! Phew.
Note: I used the flanged nuts, upside down on the top of the studs, to prevent the 2” X 6” lumber from pulling down into the stud tops.