Replying to What length el reys should i buy and where should I mount?

I think ive decided to pick up a pair of last seasons el reys, but im not sure what length I should go with. website lists 157, 164, 171, 178, 185. i've always skied 170's, but its been mostly all mountain skiing and never on a twin tip.

6ft
180lbs
intermediate, almost expert but not completely.
50/50 park/all mountain.
will hit a few pipes throughout the day, but i generally avoid them.

I know im not gonna go center mounted since i do enjoy the whole mountain, but im unsure as to where exactly i should put them.

thanks.