@Eric *********
then the METV is a good choice for you.
Updated correction ....
Each time you enter or return to Thailand during the six months validity of the METV you are stamped in for 60 days...
One 30 day extensions is allowed at Thai immigration office 1,900 Thai baht.
Must leave Thailand at end of the 90 days.
Need to show proof of insurance for two months on each entry into Thailand.
And of course get a CoE and meet other requirements to enter Thailand.