I do enjoy a variety of both styles of riding. I should also mention (although might not be applicable) that I train 6 days a week and should have the muscle to spin and turn the board. The guy mentioned with my size either board would be fine due to that. I will be boarding all season at Red Mountain in Rossland, BC.
Your last statement worries me. Will I have trouble weaving through the trees on the pro hp 157? It should still be a huge upgrade and improvement from the 162 TRS reg camber board from 2008 right?
You will be fine. A lot of the advantage in turn initiation that the TRS has over the T. Rice gets lost once you go to the wide version of the TRS, which you probably will have to do. At a size 12 you really want a mid-wide, so the T. Rice is a good match.