Dreaded lid leak on new master cylinder...ideas?

66 dart, recently swapped into disc up front, drum in the back.
Foolishly I assumed that the brand new dual well master cylinder would be leak proof, at least at the lid.

I got it installed and finally got it bled after 10 times, and now I see leaking coming from the top, and is nicely rusting the metal. The bail keeper is pretty tight already, I have to use a screwdriver to pry it on/off. The rubber gasket seems to not be able to fully seat/seal and getting lots of leakage mainly from the front of the lid. Has anyone figured out a fix for this?? Other than removing it again and filing down the mating surface? I prefer to not remove it (ever again). help
look at this horrible pic. this is 3 days old.
I just took it for a spin, and then looked at it again and fresh fluid was all over the upper fron portion of the MC, running down from the lid. All fittings are leak free.mcseal.jpg