Not a diagram, but maybe a picture is worth a few words?

Here's the business end of my cartoon-scale Mooney, with the tank installed.  This is my current favorite way of mounting tanks on profiles.

Simple "RC-style" plumbing -- no uniflow, muffler pressure, just run an overflow to the top of the tank and use it for pressure, with the clunk going to the venturi.  If you put it on the outboard side, be sure to mount it flat to the fuselage -- the clunk will insure fuel pickup, and you don't want the edge of the tank too far outboard of the venturi or it'll mess up fuel flow.  (Mounting it on the inboard side is rumored to give better speed regulation, because the plane will tend to go richer as it goes faster.  I don't know how true that is, but my planes certainly like it).

On a full-fuselage, I'd just mount it with the wide dimension going side to side, and plumb it the same way.  Some people report good success plumbing them for uniflow, by running a uniflow vent along the outboard wall of the tank, or running an extra clunk on the uniflow.  I never got that to work right, but I can't dispute those who have.