Good one, Kanga.
Bruce, regarding the rest of your question - place a valve between the return pump and return line. This will allow you to adjust the flow rate. Also agg unions wherever you have equipment that you would want to remove (such as the return pump), it just makes it so much easier when you need to clean that equipment.
To "upgrade" Kanga's sketch, you could add a "T" and second valve to the return line just above the sump, as you will someday need to add a phosphate reactor, calcium reactor, chiller, or something ??? to the system, and then the plumbing for it is already done.
Depending on the type of skimmer, you could also keep the skimmer outside the sump, and plumb on of the down flow pipes directly to it and then have the skimmer discharge into the sump.
Lastly, if you are still in the planning stage, I would recommend that you have the tank drilled for a closed-loop system as well.
Hennie