September 2020 is still a long way ahead. Things can change in the mean time, but looking at the current situation for
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months a year, the best option is the Non Immigrant O-A visa, or second the Non Immigrant O visa with later the Extension of Stay and then the Multiple Entry Tourist Visa. a Health insurance should not be the decider of getting a visa or not, health insurance in case off, is always recommended to have, as Thai hospitals are not free for use or cheap if needed.