I got the sizing on my master cylinders directly from Tilton. Their tech support is great...they offer assistance without talking down to you or trying to sell you big $$$$$ items you don't need.
Anyway, they took weight (anticipated at the time) of my car, weight distribution, front/rear rotor sizes, caliper piston areas, and other variables to recommend master cylinder size. I told them I wanted to lean toward relatively light pedal pressure, and I followed the sizing they recommended. Once it was all working though, because of my pedal position I found I was getting just a bit more pedal travel than I was comfortable with, hence the switch in the pedal pivot/leverage.
As I see it, the only thing I can do now to lower pedal effort would be to try a grippier pad compound, which I am doing. Other than that, I imagine it is just a matter of getting used to the increased pedal pressure. My other track car has power brakes, which I suspect is why I was a bit surprised at the effort required in the Datsun.
The effort required by track pads always decreases as they heat up...so there's that to keep in mind.