Hello, i didnt follow a particular program, like you i read alot of stuff and i just tried doing exercises as often as it crossed my mind, i think that relaxing those muscles is the only way to stop from PE-ing, i find cutting off the flow impossible since you use those very muscles when you ejaculate, having them tense while ejaculating just leads to a much more intense orgasm and shooting alot farther, if you know what i mean. What i think happened is it helped my self control, to some extent i can delay an erection or ejaculating, especially right after i did these exercises.
I doubt ejaculating works the same way as urinating, nature's goal is to make you ejaculate as fast as possible so implementing a way to stop semen from leaving the body seems highly unlikely, while urinating is a totally different body function wich unless delayed, most of the times...makes a big mess.
So i consider learning how to control yourself and how to properly relax during intercourse is the way to go, it has helped me but not as much as i would have wanted, i'll keep doing these exercises and with time maybe i will reach the desired outcome.