Well, in your case, it will be by "weight" so same as any other same age
Ibiza 130PD ManTran and probably "Sports suspension" - really just get a copy of your CAR DATA and off you go, no guessing.
Edit:- sorry you talk about getting struts, so I'm guessing your are replacing the top mounts, top bearing, struts and springs - is so, again beware that there are a few strut damper options, again defined by a PR code like the springs.