Are you sure your brakes will work if you seal them with some liquid glue and a rubber o-ring that is already squeezing out at the edges of the hexagon? IMHO these seals are never meant to take the pressure of a hydraulic brake. I would not ride with you....
Update:
Finally stopped the leak. Doubling the copper washers did not work. Bought these speciality washers from Earls, recommended by someone over on the HAMB and also used this sealant recommended by 19forty. Thanks for all the suggestions and hopefully this helps somebody with the same problem in the future.
I had the same issue with a new master cylinder a couple years ago that I purchased from Dennis Carpenter. Leaked in the exact same spot. I tried multiple times with different washers without resolve. It seemed to me that the master cylinder outlet port was not drilled squarely and was drilled at an angle from looking at the washer. They were only seating on one side of the washers. Ordered a new replacement master cylinder, washers and block fitting from the early ford store and that solved the problem.
Nate