Brake Bias Questions

[Project D]

OEM: 68/32%
RX7 caliper + mini discs: 72/28%

Note: that's without taking into account the original proportioning valve (that limit the pressure on the rear) and with pads with the same µ F/R

Also, "Bias adjuster" (the knob that control a balance bar) is only available on pedal box (independent master cylinder per axle)
Proportioning valve and bias adjuster are totally different things and have a different purpose.

Personally I wouldn't bother. The faster you go the more front bias you need, so having less braking force on the rear shouldn't have any hill effect especially with good tires.

Now if you absolutely want to get close to the original brake balance, the best option would be to go with bigger discs on the rear. (require custom brackets)