Don't know if you have woodchips or something to the edge of your evergreens or mow under them, but in the latter case Moon and Gater boy may have your ideal solution (this argument may not exist if you trim the trees really high or not at all; though still a good solution).
In the former case, or if you want to look cool (all other things being equal this can be a valid consideration! /forums/images/graemlins/cool.gif ) riding around your new ZTR, I don't think you have too many wrong choices. I really enjoyed reading your situation, because it is one of the first I've seen on TBN so far that really makes sense for a resisdential unit (I think Bird and a few others have them, but would have posted before my time).
That being said (and assuming you're still looking at ZTRs), since you want twin cylinder and the 44 sounds like it fits you anyway, Gamble is definitely right about the comparison, so I'd say Zforce 44.