Unfortunately, the last repair did not hold. The caulk I had used to seal the joint had completely disintegrated which led to further water intrusion and damage. The steel plates were rusting and almost completely delaminated. What a mess!
Steps:
Completely removed all rotted wood, caulking and eternabond. Resealed the joints with Titebond Metal roof sealant.
After the wood was completely dry, I applied Minwax hardener (2 coats) to all of the exposed bare wood followed up with 2 layers of Minwax High Performance filler. I suppose I could've used regular bondo but I've had great success with this combo on my decking. This stuff starts drying quick! Sanded enough to get it as level and flat as possible. Next day, I Flex-Sealed the repaired areas.
Purchased (3) .050 304 SS door kick panels. Although I only needed two for the sides, I needed to support the center roller. These were pretty expensive ($45 ea) but they were predrilled (screws included) and the exact length/width I needed. Mounted them with a waterproof adhesive and screwed them down.
Waited 2 days for everything to cure brought in the slide and it finally operated like it was supposed to. No noise or shaking and the SS panels are not creasing (which was an initial concern) so right now I'm going to consider this a success