Both bushings have been in the freezer for a few days. But the first one thawed out while I was dealing with the pocket issues. I'm using silicon based lube.
Good news though. Spent another hour cleaning rust out of the pocket and sanded it smooth. Thankfully the pocket isn't RUSTED through (all I need right now is a new subframe project

), but it was on its way for sure. Just thick areas of surface cancer in there where the rubber bushing had degraded. Pocket went back to the factory black finish though, even after somewhat heavy Dremeling/sanding. Gotta love Benz quality.
Took the second bushing out of the freezer and it seated 3/4 of the way almost immediately. A little "working" and few dead blow hammer hits to the subframe and it seated with less than 1/8" to go. I will leave it jacked up for an hour or so and it should go down the rest of the way. Thank god.