Building an AYC/ACD bleeding controller. Need help.

I'm interested in building my own control box to activate the AYC/ACD pump for purposes of diagnosis and bleeding. I know of the one for rent but I live in the U.S. and would rather have my own instead of renting one from overseas. The vehicle it would be used on is our E7 racecar.
My question is, do the proportioning valves have to be modulated (PWM'd) or can they handle 100 percent duty cycle? I guess the same question goes for the direction valves. Are they all able to handle 12 volts sent straight to them?

Another cool feature I want to incorporate is an LCD on the control box that displays pressure from the pressure sensor which is beyond me, but my electrical engineering friend says it won't be a problem, as long as I can come up with the equation of Voltage at given Pressures. I can take the sensor off of our unit and send 5 volts and ground to it and then see what the voltage reading is at different pressures (I will just use air), but if someone knows what the values are already, that would save me some time.

I know the pressure display won't tell me if the sensor is bad or not, so if I'm getting a low reading, i'll just have to use a regular pressure gauge to verify the reading.

Thanks for the help and I'll try to answer any questions you guys have.