Well, the offical HST poster shows only 10" with the 155 on bare gel and 11" in heavy clothing. That's a bit shallow for my taste. The 165 gets 12-13.25"
I prefer the 180 the most. Biggest expansion, best (or tied for best) penetration and softest shooting.
All these are great choices. Given that, I think shootability and availability move up in terms of importance.