rocker panel prep and rust proofing

[dracko]

So i'm deep into the floor/rocker/kick panel/A pilar rust repair on my '64.

Ready to weld the outer rocker panel on and wondering if I should use some seam sealer to completely seal up all seams and drainage grooves?

I see they're designed to let trapped water in the cab run down into the rocker and then out the bottom, based on how these rockers looked the design is flawed. Anybody sealed'em up tight? I am sandblasting the panels to bare metal and coating with KBS rust seal as well.