Would you attempt to put these scales on buttercream?  Should I cut them out and let them dry completely.  Customer wants a 10" 6" with scales on the bottom but only wants buttercream  I'm afraid it will pull the icing off.http://www.cakecentral.com/g/i/3045628/little-mermaid-cake-fondant-scales-disco-dust-candy-shells-modeling-chocolate-rock-dragees/

See my link.  I put the petals on crusting buttercream.  It held up but when the cake was cut they fell off.  I would probably let the cutouts dry a bit so they will be more manageable and will not lose their shape as you place them on the cake.

http://www.cakecentral.com/g/i/3145698/a/3428623/i-made-this-for-my-daughter-039-s-37th-birthday-buttercream-with-fondant-and-gumpaste-flower/