@Barb *****
Then that's the first thing you need to figure out. The non-O is what most people use because they don't want to be stuck purchasing required insurance every year, forever.
But for both of them, you can use your US bank statements to get the visa from the embassy, but in Thailand your US bank statements mean nothing. You'll need to put 800,000 in a Thai bank account, at least for the first year.