Well my current board is a Custom 2005 (154 I believe) and I think i would rather go twin because I'd like a board to be good for jibbing ect but i dont want to give up good edge hold to be able to do it.
The other thing that's been bugging me: I currently ride a 154, but recently i've read that board length is decided almost soley by weight. When i bought my board i was advised (possibly incorrectly) that it should come up to about my chin. But my 154 Custom has always ridden fine, carves well not the best pop but i wouldn't attribute that to the shorter length? So is it a just an unfounded prejudice for the longer board?
The Jam 156 will be a great choice for you. It will out edge your 2005 custom and will add in that ultra-friendly TBT feel.
Yes, buying by height (rider height or tip to tip board length) is not the way to go. It is a shot in the dark method of finding a board. Sometimes you will hit the mark, but just as often you will miss. Weight and foot size are the correct sizing indicators.