Youll have a blizzard of advice on this, so ill just say: its a NON O visa: you have to apply additionally for multi entry: and the 800K needs to have been in the bank for at least 2 months when you apply at the start.
Tod may I ask: if you enter on a 45 tourist visa, then get a Non O Visa whilst in Thailand: is the progression to the retirement extension still the same ?