For some passionate responses, check out this thread
IMO many rec skiers will not notice a huge difference in subtle differences unless you are a carver, on performance gear on hard snow and ice. The softer and deeper the snow, the more forgiving the gear and the less you carve, the less absolute accuracy of bevels come into play for the average skier and are less of a concern or issue to over think, but definitely keep 'em close, smooth and without burrs. I also agree with and think the 1° base & 2 to 3° side bevel is a good all around combo to shoot for with rec tuners and skiers.
As with anything, experience, time and trial and error will be your best guide. Unless you really aren't paying attention or using common sense, I'd say you have to try to screw your skis up enough to make a substantial or unfixable difference.