If you notice on that thread i too spent many weeks tweaking GTL, starting at +10 +5 +10 +10, going all the way to negatives and as high as +25's, and in the end i ended up back at +10 +5 +10 +10, it was the NB GTL that ended up needing tweaked as i raised FSB, requiring +3 for 421 and 435fsb and +5 for 450fsb.

I think most of my work was actually recorded in the overclocking thread, god knows where that is now though