Punter, u can stick the soft felt ones (grey from MarkC or who-ever else has them) and put them between the plastic pincab ones no problems.
It is only very thin and with the overall package being squuezed tightly with the leg bolts done up, u dont even notice they are there.  I will be doing that straight away with my NIB AC/DC. Without the felt between , the pincab ones can leave an indented line when tightened up properly, hence adding the felt is a must IMO.