When I fill in the two basic fields on the eVisa website, I get: "You are not eligible to apply for a visa through Thai E-Visa system. Please apply for a visa in person at the nearest Thai Embassy or Consulate.". That's kinda why I posted this message.
I mean I could probably go there in person and try and make sure they put Non-Imm O in the box marked "for official use", but is that a guarantee they won't just add "-A" if they feel like it? 😁