Doesn't really matter which test you give her. Prop will kick in faster and allow you to stop quickly if sides appear. If you can get prop that would be your best bet. If not out of your choices I would pick sus...
Instead of using more of the common steroids, why not try something like Androsol, that spray by P. Arnold, or 4-Aderm? There is no problem with injections and less likely to cause virilizing side effects.