That's good advice. Many valves are available, but each one was designed for a certain application. The proportioning can vary radically from vehicle to vehicle.
The factors are the amount of braking by the drums vs the discs, and the vehicle weight balance front to rear.
A Scout would have about the same parameters as a Jeepster.
One other thing that needs to be considered too is the fact that disc pads are right up against the disc, so just a tiny bit of pressure starts the braking - where drum's shoes are back a little - it takes some pressure and movement just to get them in position.
Then, once everything is in position, the disc brakes need more hydraulic pressure to get the same braking effort - drum types are more self activating once pressure is applied. So the drum hydraulic pressure needs to be less.
Using the proper master cylinder that was used with the disc brakes solves most of that problem, as the master's cylinder bores are different sizes.
So each installation is a little different depending on what donor parts were used, and in what combination.
There are adjustable proportioning valves available too - you tailer it to your needs.
Not fun if the front works and the back doesn't much, or vice versa. Both ways tends to make the vehicle want to swap ends. Properly set up they are wonderful, improperly they are downright scarey.