I dont think it will be a problem. It is not that one form of lettering scheme gives an advantage over the other.I do not use the Specffz Lettering Scheme for memorizing, since I think I am better at my own Memorization Scheme. Can this be the problem in my memorization?
My lettering scheme is not used by anyone in the world. I learnt from a 12 year old Youtube tutorial, the best way I can describe it is a mix between chinese way of lettering, and spiral lettering around the cube.
TLDR, it is totally fine with having your own lettering scheme.