Is there any harm to bench bleed the MC with the Combination Proportioning Valve already hooked up? Looking for some tricks about the least messy way to install a bench bled system in the car. If I understand right, then I have to attach the brake lines while brake fluid is dripping. So I have work fast and have some cloth in the car to avoid brake fluid spilling. Additional I plan to preload the pedal, so that the piston prevents the fluid to leave the reservoir. Any better way to do it?