Dustin Urban in BV is amazing! He did two classes last year for Colorado Whitewater at the Myers Pool. I learned a lot!
Also if Stephen Wright comes through Colorado late winter (like he has the last few years) He has a great class called Freestyle Fundamentals. I learned so much from him. I've done the class two times and would gladly take it again. He has offered these classes through Colorado Whitewater and the Lyons Kids Kayak Club.
As you know flat-water freestyle is the best thing you can do for your paddling in the winter (summer too). It will help all the types of paddling you do with boat control, bombproof rolling, general fitness and flexibility.
I'm not sure what Colorado Whitewater is offering for freestyle this year in the pool but you might keep an eye on their site- Colorado Whitewater - Kayak Classes