Used a cargo strap to pull the panels tight for fitting. Ran a pencil down the side of the keel strip to get a scribe line, pulled the panel off and planed the high spots down with a Stanley #5 Jack plane.
Did both sides, all 4 panels.
Plywood panel edges are hard to plane, with the ply grain running different directions. My plane iron needed sharpening so I finally pulled out the Work Sharp 3000 power sharpener and tried it out. I have never been a pro at hand sharpening, usually end up butchering a blade, the WS3000 worked great and I had a nice sharp blade to do the plywood edge.
It even cleaned up my cheapo demolition chisel!
Log of ZSA ZSA.