Modifying fins

I have a pointy raked fin that I was thinking about adding a bunch of layers on to get a more pivot-like fin. Anybody out there had luck building up cloth layers on existing fins to modify them?

I hate to alter a fin because the modification might not work and you lose the original fin, unless it’s a horrid fin from the start, but it’s possible to add on.
Each fin has a uniformity of density, weave intergration and unity of chemical bonding all layers together, and these things can be a problem when you start adding on, but maybe you’re doing something more than just adding a bit on…?
Can you supply a photo of the fin in question and proposed alteration or is this more a theoretical question ?