73 Manual Disc/drum Master cyl no residual valve

Took me a minute

You DO have 4x disks, right? Why are you worried about residual valves. Disk brakes should not have 'em

But I agree, at this point I'd say an adjustable valve.

I only got my car together for a bit this summer with the 4x disks (Versailles rear, 73/4 Duster front) and it seems fine with NO prop valve, but of course tires, etc, all affects this.