The reason the truck in the picture has two waste gates is because it has a divided flange with two charge pipes.
The feed line is usually run off the side of the block above the oil filter (I am guessing you tapped that for your oil pressure gauge). The drain back is usually ran to the pan or timing cover. It needs be entering above the oil line and the feedback line itself needs to be ran relatively straight down (unless you want to run a scavenging pump).
I was sent to a training one time for finance/non-profit business models/executive management and one thing they kept saying was "Perfect is the enemy of good." I am all for everything being perfect in a set up (and I have redone a lot of stuff that I didn't like the first time) but don't get so caught up in the details that it stops you or makes you spend 5k in parts. Case in point:
http://www.sloppymechanics.com/ He/they do a lot of stuff I wouldn't but it there is tons of information and real world testing. Be sure to read the wiki page and you will learn way more than trying to piece together info from various threads.