Not exactly sure which tech article you were looking at or which brake conversion components you had in mind, but most of CPP's master cylinder and master cylinder/booster setups come with a proportioning valve already installed inline.
If you take a look a some of the pictures they include with the parts, the proportioning valve is the brass block that is about 1"x2"x4" that is normally mounted to a plate just below and/or in front of the master cylinder. The brake lines run from the discharge ports on the master cylinder to the proportioning valve and then out to the brakes.
Hope this helps.
Jeff
Some sound advice should you find yourself at the controls of an aircraft...
"Try to stay in the middle of the air. Do not go near the edges of it. The edges of the air can be recognized by the appearance of ground, buildings, sea, trees and interstellar space. It is much more difficult to fly there."
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