I think the finish would be hard to achieve unfortunately to make it completely worth your while.
Its not a sin of course
As its your shell to do as you wish with. I would simply note that even the common ones hold a rather good value which means its quite an expensive experiment potentially.
They are a nightmare to track down and it can take years of searching plus a lot of luck and some $$ savings. If it was me I would save while keeping up the search. However, if you do decide to try, I really hope you can get the perfect shade