as long as the pump itself is below any kettles or pots does it really matter if you have the inlet and outlet horizontal or vertical? Is it best to have a valve at the pump ( inlet or outlet ) and or at the kettle entrance/ports??
I have found that you either want the outlet UP, or horizontal. Below is a picture of mine. You will also want a valve at the OUT let and a valve on all of your vessels. I recommend 1/2" tubing and components.