Just wanted to clarify how I do my calcs in case someone misreads and runs into trouble trying it. For approach speeds that are not stated in the POH, whether in the clean or landing config I always use the 1.3 multiple but my starting number(s) for each config are taken from the bottom of the airspeed indicator green or white ranges then deducting 1MPH for each 80lbs I am under gross then apply the 1.3 to a standard and 1.25 for a short field landing.
Sounds a bit complicated. How about flight manual speed on final, round out and then hold off until the aeroplane doesn't want to fly any more. Failing a flight manual, 1.3x stall speed for the configuration.