210lbs is fairly big for the 57 especially if you are wanting some powder. Powder and park boards do not match up...longer for pow, shorter for park. I would think the smallest you would want to go in the TRS is 59 but 62 may be better (for your weight) if you want to ride everything.
yeah i realise the two types of riding dont go hand in hand but im trying to get the best of both, which i was informed would be this board. i was thinking more along the lines of the 159 just so its still reasonable in the park, im kinda thinkin i've gotta sacrifice something! is there anything else you' reckon lads?