I believe the OP is asking about a race course that is consistently ice. You don't really have the luxury in gates of picking and choosing the type of snow you are going to initiate a turn on like you do free skiing. So yes it makes sense to begin or tuen on softer snow, but what if there is non?
A couple of observations from my gate experience.
#1. There are definitely master's or cheater Gs skis that will hold an edge like nobody's business. Case in point Atomic D2 Race Gs non-FIS.
#2. Too stiff a ski longitudinally fro a particular racer is going to be a detriment on ice. You have got to get the ski bent into an arc and if you can't bend the ski you can't carve on ice. Which brings me to #3 and #4
#3.You absolutely must have the proper tune/bevel angles. I would submit that in GS this is a .7 to true 1 degree base bevel and a 3 or 4 degree side edge. A 1 degree or 2 degree side edge simply will not due. I had the pleasure of skiing a Head i.speed in a 180 with a 2 degree side edge back to back in the same course with my more flexible 177cm Supershape speed with a 3 degreeside edge.
Yep, the SS speed held much better. I attribute it to 2 characteristics:The increased side edge bevel and the softer longitudinal flex.
#4. The above discussion about getting on your new outside ski before the fall line is crucial. A great and very easy drill is to traverse a moderate pitch in a normal traverse position and while still traversing get up on the little toe edge of the uphill ski. stay there until you decide to turn and then roll the uphill ski from the little toe edge to the big toe edge to initiate the turn. when you finish back in traverse position, on your downhill ski, you again step onto the uphill skis as before and initiate the turn on the uphill ski only.
#5. Supple ankles. There is a tendency to get stiff in a race course particularly a very icy course. You must be extremely focused but let your ankles stay supple, not locked.
#6. this is going to sound a bit crazy, but you really need to pressure your tips in the opposite direction of the turn. If you press on the ski directly on the edges you are trying to engage in the the same direction as you want to turn you are going to slip and chatter every time. And the steeper the pitch the worse it is. you must let your tips drop slightly away from your intended travel path towards the fall line not try to press your edges across the fall line and let the tips hook up. This will begin the tip bending and allow the ski to begin to arc. this move is very un-intuitive. The otter part of the equation is progressive pressure.
Good point slider. The skier demoing the upside-down traverse is too square to his feet. There needs to be a leading inside hip/shoulder/hand. Then you'll drive through the boot instead of laterally into in.
Skiing ice is about early edge engagement. Being on edge a slicing before you get to the ice instead of trying to push harder into the ice.
Ask your self this. Do I look at the ice as I come to it or am I looking at the snow after the ice? Most people, when they see ice, stair right at it even to the point that they are on it. Think about what that does to your body position.
Getting on those edges early and slicing and then looking ahead in the course you can move through the ice before you even get to it.