I am a long time Epic lurker and very rarely a poster (Sorry about that).
It’s good to see another member of the “Ginsu knife / I like sharp edges club.”.
Over the past few years I have become fanatical about sharpening and maintaining the edges of everyone in our “Ski fleet”…There are three of us in my family and we get out as often as we can.
I get my bases stone ground and structured at the start of each season and cut the sidewall edge with a 7 degree SOB panzar file set up and then set the base and side angles myself.
OK now to step into this “Black art” of edge tuning.
Your questions are valid.
I start by checking for any edge damage / nicks or burrs and tune these out with a combination of gummi stones, 100 grit diamond stone, hard Arkansas stone, and a clear super fine / translucent Arkansas stone.
After that I hit the sides with a 100 grit diamond stone (Moonflex) in a SOB edge guide.
This conditions the edge for a couple passes with a hard chromed fine / 20 TPM 8” 2 pass Swix file.
I use the file every couple of trips out but do not remove much material.
I rely more on the stones to get the edges smooth and set up properly…
I work the tips, waist, and tail in three passes, along with a couple of quick “one stroke” / length of the ski passes using a succession of 100, 200, 400, 600, and 1500 diamond stones dipped in water combines with a 20 ish percent mix of denatured alcohol and a little dish soap.
100, 200, and 400 grit are your workhorses
It really only takes a few passes of each grit.
I am polishing and working the metal to ensure a sliky smooth edge rather than taking off much material.
I finish with a Swix white ceramic stone and lastly with a translucent Arkansas stone
(Tognar has these http://www.tognar.com/arkansas-stone-hard-or-translucent-3-dans-whetstone/)
As for how to know when the edge is sharp, it’s funny how a freshly filed edge “feels” sharp when typically all you are feeling is the edge hanger or a bur.
If you progressed as outlined about with the stones your edges will be sharp.
Tognar / Ski Visions offer a plastic “tuning” stick to help let you know if the edges are sharp enough.
Good luck and enjoy!
Tuning is great “post skiing” therapy!