I made a Thai Will with my wife as the administrator and I have an Australian Will with my son as the administrator. All fixed and I don't use the 800k in the bank, I use the monthly deposits. Still run about 600k in my account just in case it's needed.
The Thai will a Superficies for the house was $1,500AUD 5 years ago.
I think you should be asking a Thai lawyer the best way.
@Brian ********
can help.