Residual valve v. s. a Adjustable Proportioning valve

Hi,
My first questions on this excellent forum. I plan to switch from drums (front) to discs (a Wilwood kit) on my 1966 Chrysler 300. My intention is to keep my Single M / C.

To get a faster response and that the rear brakes are engaged before the front brakes, I intend to install a 10 lb residual valve on the rear brake line. I see that some mount an adjustable proportioning valveon the rear brake line. See the attached diagram.

This valve can, as far as I understand, only decrease the...

Residual valve v. s. a Adjustable Proportioning valve