Glad to see you were persistent and didn't give up when things got a little difficult! Now, one more suggestion, if I may- - - -Before reassembling the master cylinder with a new rebuilding kit, soak the entire casting in 90% rubbing alcohol for a few hours. It's readily available (and cheap) at any drug store. Some of the solvents and lubricants you've been using do not play nice with rubber brake parts such as flex hoses and wheel cylinder cups. Since most brake fluid except the silicone-based stuff which really shouldn't be used in a stovebolt system anyway is basically a mixture of alcohol and glycerine, using high-proof alcohol as a cleaning solvent assures you the best chance of getting all the other chemicals out without leaving harmful residues behind. Any residual alcohol also evaporates quickly.
Jerry
