That RT AF script can be also found in the newer versons of Atuner.
And it's a lot easier to use.
It's under the "D3D Extra Options Panel", then click on "Optimise Anisotropic Filtering"
I gained about 20% across the board, with the setting optimised and couldn't see any drop in IQ.
This is a great thread, StealthHawk. Perhaps it can become a sticky ?