If you want to continue with OA Visa just keep applying at local immigration office every year, you will need the 800,000 baht in your Thai bank account 3 months prior.
If you want to change to the Non O Visa after the second year of Non OA just leave Thailand without a re-entry permit and enter Thailand again for a 30 day visa exempt in which time you can apply for the Non O, you will still need the money in your bank but not health insurance.
Mark JacobsIf you want to remain on the OA Visa you need the 800,000 baht in a Thai bank account.
If you bounce out just before your first year you will not need a re-entry permit. If you need to leave Thailand during your second year you will need a re-entry permit.
At the end of your second year you will need to apply to extend your OA Visa at your local immigration centre.