I used to have a set of blades, 99.9cms, great for messing around on and good for your carving techique, just avoid deep snow!!
Twin tips are the way forward, even if you can't ski backwards you create rooster tails of snow when you carve, good for spraying your buddies when you overtake!!
I ski every year and generally ski pretty fast/hard, I eat like a horse and and drink like a fish at apre and never come back any heavier!! They recomend 2500 cal a day for a man, I think I'm nearer 4000 plus when skiing!!
Either way, have a great trip.