@Don *****
I didn't bother to read the comments so this might have been stated already
You CANNOT go to a 90 day Non-Immigrant Type-O visa based on being over 50 from amnesty :(
It's because in Bangkok you need at LEAST 15 "real" days left on your current entry stamp <- and if you're on amnesty your current entry stamp expired a good while ago.
Also to apply for a Non-O visa INSIDE the country you must show that the 800K baht was transferred in from oversea AND there is no 'seasoning' <- ( meaning to apply for the 90 day non-O VISA all you show is that the money came from abroad) it is only when you go to apply for the yearly extension that you need to show the funds were in your account for 2 months before you apply.
AND just so you know, IF you could apply for the in country Non-O visa (which you can't from amnesty) the application would go under consideration for 14 days and then you would go back and get the 90 day Non-O visa and a new 90 day entry stamp inked into your passport. <- that's why you need at least 15 real days left on your current entry stamp (to cover the under consideration period).