Well, it took a while.
I went and rigged up an attempt with 18 gauge steel and cutdown 91 Caprice rear armrest supports, but wasn't happy with the results. Though about it for a while, until a couple of 91-91 RMW's showed up at Pick N Pull's within a 150 mile radius...while obtaining other important parts, I noticed that there were steel armrest supports for the front door panels. "Hmm..?" I thought. Drilled out the rivets and brought 'em home.
Turns out the 94 RMW wagon has the mounting holes for these still drilled.
(passenger door, driver's is similar) Arrows point to pre-drilled holes...
These are close but a bit low. So, measure up 1/2 inch on all four holes and redrill for your favorite fastener, I like using 10/24 rivnuts, so I drill a 5/16 hole with a step drill. Comes out like this...
You need to cut out a notch at the front edge of the armrest support to clear the window switch...
Provides enough support that you can put weight on the armrest...Not hundreds of pounds, but you can stop treating the arm rests as delicate flowers on the 94-96 RM.
I thought of using the built-in threaded speed nuts to fasten the arm rest to the support, but with the fragility of the door panels, I didn't wish to introduce another stress point, as the door panel has a step which raises the inside about a 1/4 inch off the support, and without building a spacer to support that gap, thought better of it.
That's what I did today to my Buick.