I'm an odd duck because I recieved part of my education in an English school and I've read of lot of English literature. Consequently, both spellings look right to me. This sometimes causes confusion. :)

I think the "warning" is basically heading well intentioned readers off at the pass. Too many people will point out "misspellings" that they find in a story without that statement.

Excepting dialogue, you should use the spelling that is proper for you. The only exception would be a first person story.