I'm in need of heel grips to keep my CLs from slipping as I walk, as well as something to keep my sling-backs from slipping down my heel. I did a search on our forum for inserts, but still have a couple questions... First question: When using inserts does the adhesive ever permanently mar or leave a sticky residue the insides of our CLS? Second question: When choosing Foot Petals does everyone choose the buttercup color? Lastly, is the general consensus that Foot Petals are the best brand to use with our CLs? TIA for your help!