Though Todd is light years ahead of me, I'm gonna disagree with him on this one. We mortals would have a hard time pulling off what a master can do in the normal course of a day.
Pick the proper tool for the job. Look at what the examiner expects of you and match your skis to the tasks.
I grabbed my favorite skis without thinking and had a rough time of the first day of on snow tasks. The examiner was a fanatic on short, round turns and doing them on a GS ski made the job that much harder. He was skiing an Elan in about 175 that had a big shovel and lots of sidecut.
My ski of choice (in retrospect) would have been a softer "intermediate" ski with lots of sidecut. Your job isn't to wax the guy in the gates or to impress him with your ability to straightline the hill, it's to demo a series of beginner and intermediate tasks.
A guy like Todd who spends 6 to 8 hours on skis every day can use a hammer to do the job of a screwdriver .... the rest of us need all the help we can get.