Hmm...interesting that your Apart is so coarse. Makes me think perhaps someone abused it a bit along the way. Might be a good candidate for some high grit sand paper love and burnishing to see if you can make it finish properly.

I agree you might have had better luck with a 208. Mine shaves comfortable off the Norton 8K. Otherwise I probably wouldn't have kept it. If the 66 is as chunky as a 208 that might have had something to do with it. My 208 is about the heaviest razor I've got, and if I'm not mindful of that it's easy to end up using a bit more pressure while shaving than I might with any other blade.

They can shave, and comfortably. Just might take a teeny bit more work than a good vintage or (much) more pricey new manufacture razor.