Educate your clientel. Slow films are good. Also, talk about films by speed, not PAN. It is confusing. Why don't you give the new Kodak emulsions a try? Everyone is talking about them on the internet. Tmax 400-2 for example. Surely that information is seeping into folk's brains and they might like to give the new film a try. It seems to me that you are really going out on a limb by stocking so much of the East European films. Or maybe not. You will be the only people stocking those for miles around.
Personally, I buy American. I can't be alone. Can I? If Kodak made paper I would buy that too.