DTV Requirements: Clarification Needed

I'm looking for clarification on the financial requirements for a DTV visa. Specifically:

1. Does the 500,000 Baht need to be in a bank account for a specific period of time before applying? If so, how long?

1. Would funds in a liquidable retirement account (such as a 401k from a previous employer or a Roth IRA) be acceptable if they can be cashed out if needed? Or do the funds need to be in a regular bank account?

Any insights or experiences would be greatly appreciated!