Hi there,
Glad you like the FW STB95, thanks for supporting Fanatic with your Hawk too. Well, when we updated the Hawk line to the Blast, the whole idea was to resolve the problems that you mention - difficulty in chop, upwind ability and control.
This is where the straighter outline, slightly further fwd fin box and fuller nose/tail, made all the difference on Blast vs Hawk - better planing/acceleration, better control as the angle of the board to the chop is different - the Blast rides with a slightly higher lift in tail/nose down - unlike the Hawk, with it's narrower tail and lots of v, which rides nose up and bashes into the chop at the mast foot - the Blast "floats" over the chop in a more "parallel position" to the chop, much like your FW STB which is the same general concept.
At the same time, we did not need to add a lot of centre width, so the Blast 115 is just 66cm wide, only a cm wider than your Hawk which is 65cm. This means it still feels very compact and loose underfoot, but it has an incredible sail range, we have used sails smaller than 5.0 and bigger than 8.0 on the 115.
I would definitely go for the Blast 115 - at 66cm, it's perfect for your 6.6, the Blast 100 is a great board too, but at 62cm it's fairly narrow and I think too close to your FW STB @60cm. Don't be afraid of the volume, the Blasts are super easy to control and have a huge wind range! Good luck!