It is possible to use both the Stacking Groups and the Positioning tabs for a single field. However be aware that the Stacking Groups tab settings take priority over the Positioning tab's. This means that if you use the “Slide Up” Group Action in the Stacking Groups tab and then use the Bottom option in the Positioning tab the Stacking Groups settings will be applied not the Positioning tab settings.
This does not affect the other settings on the Positioning tab so you will still be able to change the size and Left position of the field.
Stacking Groups Tab