I really want to do that, but I wouldn't want it to get hard for a road car.
to make this change, how to fix the cylinder master and also the actuation?
Like I said, it's a personal preference. I use a 15/16" cylinder on my car and it's my daily driver, and I much prefer the pedal effort it gives compared to the squishy, vague pedal you get with a stock booster. But that's just my opinion. I've switched all of my cars to manual disks and they're all street cars.
To change it all you'd need is the 15/16" cylinder and a new push rod, either one for a manual master cylinder or an adjustable one. DoctorDiff sells an adjustable brake pedal push rod for that purpose.
