Hi North1,
I have been using 6.2 blades for about 5 years now and am 90+kgs. I had 5.7 as my biggest before that but now have 6.2 then 5.3 for the same reason in your post. The 6.2 was a huge benefit to me and found It great for pumping onto the wave. The 2008 had a longer boom than the current shape which made it a bit trickier on the wave but it had heaps of grunt. I think the bigger sail really helps you inprove your sail handling on the wave because if you don't you will get belted when the surf is bigger.
The 2011 I am using now is way lighter and has a much shorter boom so easier to manage on a wave. I am using all severne rig( enigma boom,redline430 mast).
Last nationals at gerroa Ben Severne( thanks Ben) gave me some rigging tips as it was all his and brand new so there was no reason for the sail not to rig perfect. It did require more downhaul and outhaul than the recommended.
For east coast sailing it is great but also fun at places like margs when it is super light. I use it with a Nude 120 chopper when really light and is great fun when most people are having a hard time.
It also depends on how good your technique is too, I know a few guys my weight that can get away with smaller gear just due to there excellent techniques but for everyone else

, get the 6.2