I have wondered if used dryer sheets would make a suitable fin backer. I currently use DermaGrip Fish and Fin Glue and Silkspan. Like I said I just got back into fish mounting after my shop burned a few years ago. I agree that the Silkspan we get nowadays feels different and I definitely have issues with my fins getting wavy. No problem years ago. I am definitely open to suggestions on a new fin backing system including trying different glues also.