I like the plane the best with my Hacker also - I got the 14L though (300kV) - turning an 18x10 at first but I'm going to switch to 18x12 before I fly it again. I think with the V2 hackers, it's easier to use the 16L and the recommended 18x12. If an older Hacker, I would just open up the cooling passage and still use the same prop.

Lablover - what motor/prop are you running? Also, if you turn your throws way down, especially the elevator (mine are at about 7degrees on ail/ele) it will feel a little less floaty. I think part of the floatiness is how fast it pivots about the pitch axis. It feels floatier to me with lighter weight (just switched from 10S to 8S), but really not that bad, unless I'm just used to it. Rolls are a lot better so it makes up for it.