RE: Hypersonic 105
yes that's right, the 111 has got some more nose rocker compared to the 105. On the water, the main differences I found are: 1) 111 is somewhat easier to handle, less "stiff" directionally and easier to head on a beam reach; and 2) slightly easier to jibe. I found no big differences in floating, probably due to the lower nose on the 105 that makes a larger part of the board to contribute to buoyancy most times. I don't remember any difference in handling chop, except for the fact that the 111 keeps its nose higher and may seem safer; but actually both handled chop pretty well when sailed in the right way, which is: full throttle all of the time, and don't look down. Rather, the slightly higher nose made the 111 a better schlogger, in the sense that it tended less easily to sink its nose. As to sheer performances, I can't tell exactly, but I would not be surprised to understand that the 105 has an edge in planing and top speed.
Generally speaking, I found the 111 somewhat a more well rounded board compared to the rather "thoroughbred" character of the 105. Nothing really important to base a decision upon, anyhow; I'd rather look at other points such as general conditions and price.
Oh, just another point to think about: take a look at the fins; the 111's Drake/Curtis stock fins can be used on other slalom boards also, while those 105's odd square Drake stock fins are totally useless on other boards. So if the 111 comes with both its stock fins (34 and 42) in good shape, that is something to take into account. This can be a real point in deciding.