Yes, you probably can, but you will need to try them out to see. Please ensure that the heads of any screws used in the Buttons, or in the rebated Fixes, are flush, or just below the surface of the mouldings, so that they do not clash. See the ‘Videos’ section of the website for recommended fixings, or for more detail download the ‘Suggested Fixings for Buttonfix’ PDF from the Useful Information page.
The limiting factor dictating the maximum load is, in most cases, the pull-out load of the fixing screws, and the strength of the materials being mounted. Therefore, the fixings used should be the largest practical, given the thickness of the panel to be mounted. For Type 1 Fixes on thin panels, Varianta Euroscrews (CSK Ø6.2mm for Ø5mm pilot holes) are recommended.