Caveat, I haven't done a conversion, but I have the factory setup.  This of course uses the diesel tank.  The pickup in that tank is just a tube to the bottom with a plastic sieve at the end.  In practice, the sieve is too fine and can be plugged with algae & crud.  I replaced the sock with a coarse stainless screen with openings about half of the inner diameter of the tube.  Actual pre-filtering is accomplished with a washable screen that is mounted just ahead of the tank.  The lift pump (on the side of the injection pump) and filtering does the rest. I would think that all of this could be duplicated with the gasoline tank.