I thought I had come up with a perfect call sign, 03MO556 until I saw yours. Maybe I will go with 223 instead of 556 even though we both know it’s not the same thing. lolYeh...what they said. I usually talk Skip on SSB. Stateside USA skip I go by 556 North Carolina. International stuff I go by 2NC556 (2 November Charlie 556) for all the same reasons Shadetree Mechanic stated. Each country has their own division number...some people don't use them but most do.
Have fun