You could continue to use Justin's practice assistant to build a practice routine. It's completely customizable so you can create your own practice items and routines. You can include all, some, or none of the items from Justin's practice routines. That does require going through the website instead of the app, I believe. I like the way the practice assistant is structured.
It takes as long as it takes unless you quit - then it takes forever and you will never get there.