Dr. DIFF cobra brake/ master cylinder question

We used the existing master and we tried bleeding it while it was on the car.
You can quickly bench bleed on the car, if necessary, by plugging the two ports on MC and hand pushing the brake pedal. When you can barely move the pedal, the MC is hydraulically locked and virtually 100% sure there’s no air in the MC. Then remove the plugs one at a time and reattach the brake lines.