We'll be there in February and we plan on taking a lesson the first day we ski. (2 adults in our 40s and 2 fifteen year olds.) We ski everything from greens to blacks in Michigan, but we understand there are numerous differences between that snow and Colorado skiing. We really want the lesson just to gain an understanding of the differences so we can have the most fun skiing. How long of a lesson do you think we'll need? 2 hours? Half day? Your insight is appreciated.