I'm 5'10" 170 9.5foot 9.0 boot and have been riding the trice 157 for the last two seasons. I have about 120+ days on it. It is wide at 25.8 but with the rocker between binders it's not a problem. I like the stability as I'm more bomber than butterer. The board floats easily in deep pow. I would not downsize from the 157 unless I was strictly park and then I wouldn't be on the trice anyway.
As an aside, I demo'd the Niche Aether a few times last year which has a similar profile (directional sidecut instead of twin though) and it has 25.2 waist. I was stoked on it. Very snappy and super quick edge to edge.
Try this trick and spin it, yeah
Your head will collapse