What are my options for maintaining my retirement visa with 800k in the bank and monthly transfers?

Are we talking Baht. ??

Speaking from actual experience of switching from k to 65k rule at jomtien immigration. When my renewal was due i took 12 month evidence of 65k per month for previous 12 months. Informed immigration officer i want to switch from k to 65k rule. Immigration officer not interested in the previous 12 months of evidence showing i could comply with regulations. I also had evidence of pension salary. Again not interested. Told me to produce this evidence in 12 months when i come back to do my next extension along with bangkok bank statement showing the monthly international transfers into my account. Was not given date to come back to show i had complied with 800k in bank for 3 months as is the norm at jomtien immigration.

Yeah I'll confirm it's 800k for another 3 months then never below 400k

I would suggest, put your 800k in to a five year fixed deposit account. I get 1.25% for it with Bangkok Bank. Not only is it your visa guarantee but if things go pear shaped, you have sufficient funds to start new.

Then transfer your monthly 65k in to a seperate savings account and live of that.

The 65k needs to be direct deposited from abroad.your bank book deposits coded ( FFT ) foreign fund transfer. for a number of months, then can withdraw your nested baht.

As long as your statements show every month, for a year, your visa's fine. Once deposited, its yours to debit at will.

If less than 3 months you can make another plac it not bangkok

Start the 65k foreign transfer immediately you’ll need all 12 months and yes you need 800k in your bank for 3 months after good luck

You have to keep the entire 800k in the bank for 3 months from the date of your extension and only then can it go down to 400k for the rest of the year. Next year you need to have a full 12 months of a minimum of 65k transfers each month from overseas before you apply for your extension, once you get that extension you can withdraw the final 400k. On the plus side you don't need to keep the 65k transfers once they show correctly as from overseas in your bank you can spend them