I wholeheartedly agree with Increasing- if it made you gain then continue it. You don't need to change a single thing until you stop gaining from it. You don't even need to increase the intensity/reps until your gains stop, many people have gained from the same routine done over 6months or more.
If you didn't gain anything from JP90 I'd advise doing it for another month or two, if there's even 0.1 of an inch gain after that then I'd keep it up, if not then you can think about adding some other stretches/exercises.
All PE routines have the same basic frame though, depending on whether length or girth is wanted. A mix of stretching, jelqing, or manual girth exercises, alongside kegels edging and stamina work.