if you are dead set on running a remote filter i would use one to mount a fram PH8a sized filter. absolutely massive filter element in there. IMO i’d run a Fram Endurance FE8a filter or if you can find an OG wire backed Titanium FS8a at AAP.
otherwise you can still find OG wire backed FS5 filters at AAP and i see no reason to really add a remote filter. you wont be increasing sump size by that much and you’re adding multiple new points of potential failure.