I never realized brakes, boosters and masters, and ratios were so technical. I had that 80 GMC Olds Diesel Truck that has Hydroboost on it. The Hydroboost went **** up and it wasn't worth all the funds for a new HB unit, so I simply went to Pull A Part, paid $15 for a used but new looking booster bolted it in, used the same master and it worked like a champ. Guess I got lucky now that I see all these different ratios.
When I had a 55 Chevy sedan, I spent a lot of time on 55-57 forums. I'd guess >90% of those cars came from the factory with manual brakes, and the power brake option used an unusual booster/master combo called "treadle-vac". Anyway they are very hard, if not impossible to find, so most guys use aftermarket components.
One of the most common posts was guys having problems with their brand new aftermarket power brake kits not working as well as manual brakes. A lot of it had to do with the one-size-fits-all aftermarket kits. Typically the boosters were too small, sometimes even a single 7" diaphragm (!) and/or the MC bore too big. And then if you ever got the right combo (usually dual 9" booster and 1" MC) , the brakes would be grabby because of the manual brake pedal ratio. The fix there was to drill a pushrod hole lower on the brake pedal because the factory linkage was an afterthought and almost impossible to duplicate.
Also, using a kit's generic proportional valve to limit pressure to the rear brakes usually hurts performance. I always told guys to use a manual valve, which lets you reduce pressure ONLY if the rears lock-up prematurely.
Then there were the guys with big cams making only 10-12" vacuum at idle, which requires a HUGE amount of diaphragm area, but that's another story.
Treadle-Vac
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I've given Rep credit to all those participants, and since I'm so special, I count as double credit just so all of you know.
