i haven't done it myself, but you should be able to achieve it with the mixed method. For example, 400k in the account, and 32,500 per month in monthly transfers. Talk to your immigration office.
so where does your daily spending and bill paying money comes from. I assume you are sending it to Thailand as needed. I am guessing you are probably sending around the 65k each month anyway. So where is the difference?
but the point you're ignoring is that many are using the 65k per month, so no you are incorrect when you say they are trying up 800k. Personally I prefer to "tie up" the 800k, but that's my choice..
I had two Bangkok Bank accounts, one for my visa money, and one for daily use. I just opened a Kasikorn Thsi account last week. I opened it to split my money over a couple of banks. I only had my passport (because I had just done 90 day report), my Bangkok Bank passbooks (bookbanks), my BB debit card and my Thai Drivers Licence. I actually went to ask them what I would need, and they decided to open it with what I already had with me. It depends on who you get I guess.