Let's see if I can make some sense.

There are several ways to plumb a pump.

*) Pump from tank to carb., no return.
With this set-up, the higher pressure at the carb gives the most consistent runs but causes a rich midrange because with a two needle carb., you can lean the top and bottom but not the mid. A larger bore or Perry carb will compensate with less draw at mid and give a tad more power at top. Perry advises not to use muff press. just vent the tank, but I never could tell any difference.

*) Pump from tank to a 'T' just before to carb. then a smaller return back to a vented tank or muff pressure.
This method is good if you your carb is too rich with the above method or you have an air bleed carb and can't close down the fuel at idle. Fuel will always be 'at the carb' when nose-up so it doesn't have far to draw but will only be under the pressure of gravity when nose-down.

*) Pump from a main tank on CG to a small header tank behind the eng. Vent (overflow) it out the top and back to main, which can be vented or to muff pressure. The carb just draws out a clunk in the header tank and the pump keeps the header full till the main is dry. This method is much like the 'T' with gravity still having an affect.

*) I've even heard of pumping air into a sealed tank so the fuel is pressure fed to the carb from the clunk. This method may work but will flood a stalled eng until the pressure equalizes.

*) Some guys swear by the 'uniflow' or two line method, though I don't think it will work with a pump. I've never tried it.

Some set-ups may require a restrictor, check valve or creative fill/drain system but most can be made to work with one of the above methods.

Give me all the details on your plane - maybe I can help and fax you a diagram or something.

Hope this helps!!! Kirk