Unless your wanting an extremly professional look, I just do the following and it keeps things nice and simple, and does the job for what we need.
Continue rugging and stalling to keep it from getting any longer. Make sure his rug is warm enough to prevent the coat growing any more. If you work the horse hard, the coat should sit down. And use one of those coat shedders or grooming blocks (things that look like pumice stone) to get the longer hairs out.
I might be in a warmer climate than you tho, cos my babies never get extremly hairy to start with