I would say try to pumpmmpd often and hover longer in the 7-10Hg range than the 5-7. You WILL notice a change in size and speed of fill.
Biggest cock only pumping! Watch me growing LIVE HERE http://www.myvacspace.com/Morpheus/cartaffiliate_723/ (copy and paste link for SIZE)
10"+ X 13.5"+ MegaHUGE is my way, anything less is just HUGE, lol!