I have recently done this with immigration. For NON-O which is if you are married to Thai National (not NON-OA - which is for retirement over 50), You only need 400KB and no proof of insurance. Money definitely must be in the bank 2 months prior to your stamped passport expiry date. Doesn't matter how much time you spent in quarantine. Must be in a Thai Bank. You must have a bank teller provide an official bank statement letter (cost 100B). You can try a print out of your bank book (some clerk may accept) but the bank letter is what's requested. So make sure you have your bank account setup pretty much as soon as you arrive ! Good luck...Chok Dee