RE: i sonic
The STypes definitely will hand the chop "easier" when push comes to shove, however the ST137 will not really be so ideal with a 110Kg rider and 9.5m sail combo. With 110Kg on ST137, the sweetspot starts to end around 8.5m, but below that (sail size) would be a good hi wind/rough water blaster.
If you want to emphasize more sail area capacity plus boost the early planing with a slightly more efficent (not usually such a bad thing with bigger guys, except in extreme chop) then the iS125 will be a better solution than the ST137, albeit with a slightly more "technical" or "comitted" ride/character in choppier conditions (but not prohibitively technical, at all, especially if you are only considering sail[wind/conditions] range in 7.5m thru 9.5m/110Kg range])
If you've any further questions or need more info, please let us know.
Cheers ~ Ian