Not sure about the years. It just kept changing: 21 m, 24 m, 27 m. Who can keep up? Not me, 'cause I don't race.
American's call that Corduroy http://www.onthesnow.com/california/mammoth-mountain-ski-area/webcams.html?id=16463
Still need an answer to how much vertical you think you will have to play with.
I haven't been on any Modern GS race stock skis lately, and my quiver is pretty old, but here's two reference points for you.
Volkl P50 F1 Energy 188 cm from 2002. Don't know what kind of stock it is. Reviews just call it a serious GS ski. It seems pretty flexible to me though. I would call it more playful than serious. Radius seems to be about 21 m; 102/65/88 are the dims. Seems to be ok even on a little 300' hill, but barely.
Old-School Kästle SG 208 cm, 70 ish m radius. Can get up to speed and make two or three good turns at Blue Mountain Collingwood (720 foot vertical), not much use on a 300' hill.
If I were to get a GS ski I think I would go for somewhere around 185 cm.