I am not a visa expert but I have done a lot of reading on many forums. It seems to me that you are trying to combine the two methods - the 800,000 required and the 65,000 per month option. Separate the two in your thinking. I think you need 800,000 each initially and then once in Thailand you show 65,000 per month deposits for next year extension.
try moving to a โwesternโ country if you werenโt born there and you find out how difficult if not impossible it is and that is even if you speak their language. Thailand is far less bureaucratic than most โwesternโ countries.