I know this will sound like heresy to some people, but why bother getting the blades flat when sharp is what we are after?
I use a 6 inch chain-saw raker file and the sharpie marker comes off in less than 20 strokes per side. I then reduce pressure to almost no pressure at all and use a "count down" -- 8 strokes across a pair of blades, then 7, then 6, etc.
After the "count down" I finish the edges with very light strokes with the side of the raker file (the sides of these files have no teeth) as if I was using a sharpening steel on a butcher knife.
Shaving sharp in no time. Yes, the blades may be a little dished in, but who cares if they are razor sharp, and they still spin true?
And, raker files are really cheap at the hardware store. I make little wood handles out of 3 inch pieces of thin tree branches, and I put them on all my raker files. I always have a raker file in my pack.
This is an inexpensive and sure way to get a Snuffer or a WW shaving sharp every time.
Give it a try.
Joe