Here is a tip:
Are your visor clips loose and not holding up the visor properly? On my 560SL, I removed the plastic clip holder from above the windscreen (one phillips screw). I got my heat gun and warmed up the clip holder just unit the plastic got a very slight sheen. Then, with needle nose pliers ever so gently sqeeze down on the clip holder opening to close it up a little. Cool the part in a cup of cold water to "set" the plastic. The plastic will be soft after you heat it so be gentle with the pliers and only sqeeze it about 1/16" to 3/32". Also be sure to leave the phillips screw in the clip holder or you may not be able to get the screw back into the part after it is "resized".
My visors now snap into position with authority and hold up perfectly.