I have used for a few years the FK / SKS MultiTool with adjustable angles. It seems to do a fine job for basic recreational edge sharpening. My son is now racing and has been asking for "sharper edges". To this end I purchased from FK some files ( icecut and diamond ) and edge guides.
I believe the file prefers to be pulled towards you from tip to tail. As I did with the multitool.
I am uncertain how to mount the file in the guide; keeping the tails away from you, pulling the file towards you.... which direction does the head of the file point? towards you or away from you? ... and at what angle should the file be placed vs. perpendicular to the ski?
I have watched whatever video's I could find and no one addressed this exactly.
Any comments would be appreciated. All the best....