I have been skating 159's on decks between 8.5 - 9.0 for a few years now, I couldn't imagine using a smaller truck with those kinds of shaped boards (everyone has their preferences).
I recently just ordered some 169's (as I have been riding a 9.125 egg shape), and wanted to see what that little bit of extra width will feel like (mostly for cruising around park tranny / grinding coping).
Hopefully they won't feel 'too big', or stick out too much to feel snowboardy. I would say stick with some 159's, unless you are going to be consistently skating boards that are 9+, or have some kinda of really specific type of skating / terrain in mind.