Ok. I was trying to be funny with the title.
MINUS THE POWDER, just hard pack, groomers, park on small PA hills
LOL sorry my sarcasm meter is on the fritz today!
Yeah, on hardpack you still want the longest effective edge you can reasonably handle, and a longer sidecut radius will mean you've got to lean the board more to get the same turn. There's a reason the race boards are super long and have super long sidecut radii!
Again, I still think they're a little short for your weight. The 154 will probably be fine, but longer wouldn't hurt if you want to carve on hardpack.