FlightDetent
42t and 75t, even with some tail-wind it works like a charm
You are talking about weights ranging from pretty much BEW or a green A/C with no pax and min fuel all the way through to 10t over MLW depending on which variant... quite the range. In both the 319 and the 320 any tailwind and a LW of more than about 60t will see you not sliding down at S speed on the G/S but rather creeping away from the speed.
As someone mentioned, use the FCTM/FCOM as your reference point, then refine it as you get comfortable.