Yes, you should always put on output sided, the way I read fakr's situation, he was still restricting on output side, it was where it was going into a kettle by putting it through the kettle valve in reverse. If he was talking about restricting input side by reducing the flow into the pump you are quite correct Jake, never, ever...the pump will run dry.
Yes Globe or Gate Valves are better than ball valves, but most people use ball valves.
JQ