It's been mentioned heaps of times in other groups and hence a lot of misinformation being spread. Every possibility immigration will expect the 500k to be in a Thai bank account. Immigration has NEVER accepted funds overseas. However, with the bounce, extremely unlikely as borders do not really have the facility to scroll through bank books and account statements. I'm guessing most DTV holders will be bouncing every 180 days
When I did the OA there was no insurance. Used to be able to get a useless policy for 7700 baht which satisfied the OA requirement, I don't know if it's still available. Sure beats tying up 800k for a year or more
I switched from OA which didn't require 800k in Thailand, but during the second "free" year of the OA I did the 65k transfers so I was able to get the 90-day visa in Bangkok and the subsequent 12-month extension. Seems to be the best way to avoid the 800k lump sum