@Jeffrey ******
I made that move a few months ago!
I went to the Bkk Bank in SriRacha to ask about the 800k documents and they did them immediately. It took about 5 to 10 minutes. I then went to immigration and was finished there about 30 minutes later.
I mentioned the ATM thing because everyone should know this as they travel around Thailand as it saves money and is superb (it's also the reason some people move banks)
Good luck.