Wow a skijoring race sounds like fun.
Teawoman- I get warm very easily when I'm moving and cold very easily when I stop (and it can be even worse if I try to eat outdoors). You probably need fewer layers while you're skiing (if you'll be moving constantly leave the layer behind, if you're likely to stop and get cold tie it around your waist or carry it somehow). When going somewhere after skiing, it's always best to bring a dry shirt (I like to change the baselayer- it's the wettest and I know I'll never warm up as long as I'm wearing a wet baselayer). Glad you're enjoying skiing!