Canadian, Eh

I get asked about the spelling of jewellery fairly often, as I AM in the business of designing and creating it, after all. To be honest, I never know which spelling to use. In writing to an American, I fear that spelling it the 'real' English way would throw them off, but I would never dare to use the American version, 'jewelry', amongst Canadians or Brits. Must I continue catering to those I speak with directly, or is there a way to set in stone the spelling of my choice, never wavering from it?