For a medium spring rate, you'd want B code bars . I don't have the part numbers for those. A Ford dealer can look up the numbers based on the VIN of a torsion bar Ranger or Gen2 Explorer that was originally built with B bars.
Maybe someone on RF with factory B bars can "lend" you a VIN - that's how we got the #1 bar part numbers a few years ago. The factory-installed torsion bar code (1, B or F) is on the DS door/jamb sticker.