*Update*

I finally lapped and tried the Norton. Razor's still not getting sharp.

Lapped with 120, 220, then 400 grit sandpaper (on marble) for the 4k, which is now smooth to the touch with a very slight abrasive feel on the razor. Went up to 800 grit on the 8k side, which feel silky smooth. They're flat enough to past the grid test and create lots of suction if I put the stone down on the wet marble. Lapped off less than a 32nd of an inch from each side.

The blade was off the 1k equivalent film when I started, sharp enough to (technically) shave my face. I did an aggressive pyramid starting at 25, shave test: no go. Repeated the pyramid, still not sharp BUT definitely sharper than when I started. Tried a conservative pyramid, no noticeable improvement.

Tried again this morning. Lapped the stone, pyramid from 25, not sharp, another pyramid, still pulling, gave up and shaved my face.

This is where I was stuck with the film: noticeably sharper than the point at which it starts to cut whiskers, but nowhere close to smooth.