Ive built hand pumps with goodall type valves on the discharge side,once you get the "fit" correct for the tubing works well..they will not work on the suction side.suction side valve must be lowest possible resistance to flow,and that means ball valve.I also tried goodall type as a boiler clack,very good! absolutely leak free. but again needs to be very carefully sized so that flow resistance is as low as possible the silicone tube internal diameter should be about0.002 smaller than the sleeve.
Gordon Watson