It would be a good idea to click on the Start Here button at the top left of the page. Lots of good information on what the Gym is all about, including best practices and safety tips.
It is always recommended to start with a beginners routine (doesn't have to be the JP) and continue with it for 90 days or until you stop gaining. Start slowly and build up to the full routine over a few weeks.
Jelq with an erection level between 40 and 70%. Do not grip too tight, just enough to feel blood moving up the shaft . When stretching, grab your shaft about one inch below the glans and do not pull too hard, just enough to feel a slight stretch. Let your PIs be your guide as to how hard to do your exercise.
Your goals are possible if you are willing to be consistent and put in a number of hours a day. However, in my opinion, your goals or going to be extremely difficult to achieve. One inch plus is more realistic, but it never hurts to have a stretch goal.
Don’t forget to take good starting measurements and photos so you have a solid base to compare your gains to.