master cylinder question for 89-95

ok i now have rear disc brakes on my truck and an adjustable proportioning valve for the rear. with the stock setup there is two brake lines coming from the master cylinder body, one Ts and goes to each front corner, and the other goes to the stock proportioning valve in the rear, which has a return line that goes back to the front and Ts into the front brake lines. i read in my toyota book that this line is to send some of the pressure back to the front so the rear drum brakes dont get as much pressure as the front.

inside the master cylinder body there are two pistons and one spring for each piston, the front has a piston and the rear has a piston. my question is, is it ok to use the stock brake line outlet for the rear without that return line going back to the front, this would make sense because the pressure would be equal all the way around as long as that piston and spring for the rear create the same amount of pressure as the piston and spring in the front.

does anyone know if the front and rear brake line outlets on the master cylinder body work the same and create the same amount of pressure? i dont want to have to rerun the lines after the truck is completed.