I don't see overfilling causing a leak. I have somewhere between 6-6.5, closer to 6.5. I'm going up to the mountians next week, if it was just normal driving, I'd keep it closer to 6.
98.5 SVT
91 Escort GT (almost sold)
96 ATX Zetec (i brake to watch you swerve)
FS: SVT rear sway bar
WTB: Very cheap beater
CEG Dragon Run - October 13-15