If the pump is TOO big, then the FPR might not be able to handle it. FPR opens all the way, but the flow overwhelms it & the pressure is too high. I don't know what flow rate causes this to happen, but it'll be worst at idle.

Why do you think you need to lean it out? Why do you think you need a different pump to accomplish that? Is the fuel pressure actually too high when idling? Do you have a fuel pressure gauge?