anyone know how to equip the three special dresspheres for paine rikku and yuna?

Fill out a garment with dressphere's.
Make Yuna (for example) go throug every dressphere in the garment grid.
When that's done select the button to change dressphere again
And choose Yuna's "Special Dressphere"

Best garment grid for this use : Unerring Path