What are the official requirements for proof of savings for the DTV visa in Thailand?

I have a few questions about the proof of savings of 500k for the DTV visa.

Some seem to provide 3 months of bank statements & some 6. How many months are actually officially required?

If your savings are held in different accounts and you transfer them into the same account, how long do you have to show the full 500k in that account for them to accept it?

Another option of financial proof seems to be payslips. If you own a business and invoice clients weekly, would that be acceptable?

Do they accept proof of a certain monthly income rather than 500k savings?

Or weekly income paid by clients into a personal bank account?

Thanks