Great on benefit of tuning and flattening those skis, @GregK
. You probably know, but maybe for others, base does not need to be absolutely flat.
If the ski is flat 1/2" to 1" in from the edges, that ski will ski flat, right edge grip. Especially on a fatter ski if it's rail high, you would be wasting a lot of edge/base depth/material by completely flattening it - unnecessarily.
(Doing this flattening by hand, a lot of time and elbow grease would be wasted also.)
The 121 Revolt I have not skied. So with that caveat, I've been told that ski likes a more upright style, not so much more forward.
For me, this is a big factor. I want to be able to both ski more upright at times and drive the tips at least a bit at times, for more options in many situations.
But the Black Ops 118 has very good hold when turned right, including 1/2 tunes. (1/3 would be fine also.)
When a ski is tuned right, for normal, more traditional skiing and for freeriding, it doesn't need a gummy de-tuning. Instead, it sometimes benefits from doing what most racers do: increase the base bevel towards tip (and usually tail), in a graduated manner, just a bit, in small increments, so as not to overdo it before testing on the slopes.
Tuning by hand, looking down on the ski base, what you're doing is steepening the drop off of the base in this way, just a bit, making the drop off of the base bevel gradually slightly steeper towards the tip and tail. Only a few
relatively short strokes will often do this, moving the closer-to-center end of these strokes towards the tips more each stroke, shorter and shorter (alternating with an occasional stroke on the edge bevel side to prevent a burr), shorter and shorter, to only a few inches long for the last of them. This is fast and easy, the edges remain sharp all along the effective edge, and the results are dramatic - the tips don't catch or get hooky. You are free to carve or pivot, your choice, on most skis.