Yeah, I think 82 too. My own 82 has been used a lot by a 85 kilo friend of mine and he seems very happy with it also in lighter winds. Only with underpowered 5.6 he complained, but then it was mostly a matter of the board feeling under finned. I reckon that if you spend some extra on a set of 15cm quad fins you will get a more "poppy" feel and better underpowered upwind with underpowered 5.3.
Regarding "feel of size" yes the 2011 Quads do feel a bit bigger then the size indicted, particularly compared to some other quads and twins on the market. But they still feel a bit smaller then last years boards (partly due to less fin area, I'd say). For example, I think the Quad82 will EASILY feel as big as the Fanatic q86 and probably even feel much more stable in light winds. This is due to some more width and a flatter deck. Boards with a lot of volume added along the centerline tend to rather get more unstable in light winds and unless you are really standing absolutely still and sinking such volume in my opinion only hurt the slogging performance.
So in summary: I'm quite sure the 82 will the THE size for you in the Starboard quad range. I know from my friends sailing it works well in light wind underpowered sailing at your weight and he thinks it feel very stable and easy and also early planing also without that much sail power (much more so than the Quatro quad 85 he had before fx). And if you add a set of bigger fins you will be able to improve upwind and planing even more, particularly with a full 5.3.