With all due respect, Wolfey... you have contributed a huge amount of information, expertise and data to this mod thread, but I see nothing gained.
I have banks of unmodified Gridseeds running on Windows 7 with the girnyau's gridseed fork of cgminer compiled for Windows by Sang with his config settings at 888MHz which are getting as good or better 24hr averages on the pool side... 350Kh/s to 360Kh/s over 40 units over 24 hours.
Same here. My unmodified miner gets poolside results of anywhere from 250-500 kh/s. Using the 500 kh/s spike to make any claims doesn't make a lot of sense. My average rate is somewhere around 360-370.
As has been said many times in this thread, a faster hashrate does not necessarily mean better overall performance. The rest of the miner needs to be taken into account. I can think of several issues off the top of my head that would prevent improved performance (and even worse performance) with overclocking. Even the firmware could become an issue (ever played an old DOS game that didn't have an FPS limiter on a modern machine?).
I'm waiting to see what the numbers look like after another 24 hours.