@Dave ********
You can do it either way. You can get the 90-day non-O visa in another country and enter on that, and then once in Thailand, with
*****
days remaining on the visa, get a 12-month extension at immigration OR enter on visa exempt, obtain the 90-day non-O visa at immigration, and then with
*****
days remaining get the 12-month extension. It's your choice, whatever is easiest I guess. Getting it at an embassy means one less visit to immigration, and that seems to appeal to some people 😆