realskiers

Sidehill:  I agree with Max and the others.  No ski should be tuned flat on the base.  The skis will behave terribly on the slopes -- edges hooking and grabbing, edge-to-edge transitions unpredictable and poorly controlled.  I have rented or demoed skis that were tuned flat, and fought them all day -- some of the worst ski days I have had, and not because of weather or poor snow, just a really crappy tune.  I was exhausted after only half a day.

A 1 degree base bevel is used for most recreational skis, and is what I put on all the skis in our household, no matter their purpose -- soft snow or hard.  Further, the comment about filing a 1/4 inch in from the edge is just wrong.  You should never file more than JUST the metal edge when base filing, and once the base bevel is set with a chrome file (using a high quality file guide!), subsequent sharpening is just a light touch-up with a diamond stone to file as little as possible from the base edge (the real sharpening work is done on the side edge).  When I set the base bevel on a new pair of skis, a trick I use to make sure I don't take off too much, is to run a black felt marker along the steel, and then CAREFULLY file just enough until all the marker colour is gone, never more, and never into the P-tex base.

Side bevels are optional, depending on where you ski, how aggressive an edge you want, and your tolerance for grippy edges.  General guidelines:  1 degree side edge is what some people use for powder/soft snow skis; 2 degrees is all-purpose; 3 degrees for hard snow high performance skis.

For ALL filing or sharpening work you must use high quality bevel guides to get good results.  They really are worth the investment - I have never regretted buying decent tools, for skis or any other work, for that matter, and they pay for themselves in short order.  Swix, Toko, KUU, Holmenkol, SVST, are some of the makers of good tools and vices.  If you visit their websites, you will find good how-to guides for sharpening.  Swix has videos, too.  Some shops publish such guides on their sites too -- Slidewright is a good place to check out.

BTW, $40K may sound impressive for a tuning machine, but it really isn't.  A serious shop will have a Wintersteiger or Montana (both German or Swiss made), laser guided machine with ceramic stones that grind the bases flat, set side and edge bevels, and can be programmed to put whatever bevel angles you want, and whatever base pattern you want.  These cost at least $250K or more.  The quality of their tunes is remarkable (in the hands of a good technician in a reputable shop), and very accurate.  Go find such a shop, and ask some pointed questions of their tech about their capabilities. 

Hope this helps, but post back if you have more questions.  Glad to help.

Cheers, and welcome to our forum.