I was hoping for the Salt Flats but ended up with the Black Hills for a wall supported work bench. It is framed by 2x4 studs that seemed straight enough and all was level as I fitted the composite sheet material between the 2' sections. But as I prepare the surface to be covered with a top of glued up 1" thick Ash boards it is like a Six Flags roller coaster, plus and minus a half inch up and down over the surface of this L shaped bench.

I have seen how one can set up a router sled jig to plane and level the surface but I am unsure how well the sub-floor material I used will plane. An electric plane does an ok job on it without the tear out I feared but this seems quite a lot of work for what is almost 20'x3' of surface. I have not ruled this out and it seems the responsible adult thing to do.

Then I had the cave man inspiration to "mud" the top with a half inch of concrete or some epoxy/adhesive/linoleum glue/etc. And then floating a sheet of 1/4" ply on top to create a flat and level surface to have as a base for the Ash boards. The squeeze out would make an Eclair blush but this might be quicker than planing the surface. Not all that original, I have seen it done when an old floor is to be tiled.

I am unlikely to make the cover of any of the Woodworking magazines in any event. This is not to be confused with elegant craftsmanship. It is more like being the first responder at an auto wreck. Triage advise would be most welcome.