Thanks for the additional links to choose from. Is there a thread that compares all of the different vacu grips that you would link to?
Fuck the mandatory hand-only exercises. You can start with both hand and device assisted and possibly accelerate results (my favorite example of jelquing and using an [words=https://shop.mattersofsize.com/products/sizegenetics-penis-extender]extender[/words] as of late ... newbie with a 1.2 inch length gain in 2.5 months:
http://www.mattersofsize.com/forum/showthread.php?t=28874 ). I know the theory though - peak with the least assistance, then progress from there. But, the dick is not like a muscle ... it's totally different tissue ... as most of us ... including you ... realize. You can do any manual shit you want from the start and it will work out. It seems to mostly come down to total time stretched properly ... no matter how you are doing it.
HOWEVER, I would CERTAINLY suggest 3- preferably 6 months (at least) of a serious, dedicated manual routine - hands and or devices - before screwing around with Chemical Penis Enlargement assistance, possibly including more typical vasodilators. The next step would be surgery, and I would advise avoiding that entirely ... in this case if not in every case.