I don't think there's any practice that is both best for your own safety and also best for not startling people, unless that is simply to avoid riding on a MUP. Whatever you call out, it makes it more likely there will be a collision, except perhaps in a case where somebody is drifting into your path. And in such a case you could always choose to avoid the situation yourself by slowing down, changing your course, veering off the path, etc. I don't think there's anything you can say though that will predictably make people avoid your intended route and make them comfortable with your presence too. Some people will get the idea quickly. Others will do the opposite of what you want and would have a safer and more predictable presence by just not being aware of you.