As for the flaccid hang I notice a huge improvement from doing JP90. I finished 3 months and gained .5" erect length. I did not follow my flaccid length closely as I am less concerned with that. I am sure it increased some as well though. The improvement I notice is that when I am having good consistent workouts my penis stays plump, full, and long almost all day. I have very little to no turtling (when your penis kinda shrivels and retracts into your body). Instead I have what looks like a very mild but flaccid erection. I posted a thread about the reaction I got from my wife when she noticed it.
I own an STU and it is nothing like masturbating manually. It really is the closest thing to the real deal. Also if you are trying to treat Premature Ejac I find that my body's response to the STU is almost identical to when with a woman. There is a wealth of information here about premature ejaculation. It even has its own subforum. I wish you luck and success!