Proportioning valve or no for 65 Dart disc/drum brake conversion.

I installed ‘73 - ‘76 big bolt pattern front factory disc brakes on my ‘66 Dart with the small bolt rear 9” drums along with an adjustable proportioning valve .
With this set up the p.v. is set wide open , the 9” drums don’t seem to need one .

Later when I get around to installing my 8 1/4” axel with large bolt pattern 10” drums the p.v. may come into play .