Start reading in the Pumpers Forum. There are lots of guys there, like avocet8 and peforeal, and myself, who have made gains pumping, and like I said, the lapdist pump is a popular model, although not used by all. The main thing is to buy a quality system with thick walled cylinders and a pump with a gauge. Lapdist is one of the few that offer a brass pump, most others are plastic.
Yes, you specify the cylinder size when you order and since your 8 inch length is non-bone pressed, I am leaning more toward the 11 inch cylinder.
You are going to pump up huge, so I hope your wife is prepared!