For LTR - Wealthy Pensioner -, the requirements are pretty strict, $80k in passive income per year. That can be SS, Rental income, dividends, interest, capital gains. They will add it all together and "follow the rules". You will have to provide tax returns/evidence.
In terms of insurance, you either have to have $100k in "liquid savings" over the last 12 months (cash/deposits - investments are not accepted) or you can get the min required health insurance. AXA offers a health insurance plan for LTR (THB 300,000 deductible, THB 2,000,000 max), if you are in the 65-70 age range, it will be about THB 21,000/year.
Once a year reporting, fast track airport access for immigration and THB 50k cost for 10 years make it attractive IMHO