What are the steps to obtain an e-DTV for dental treatment in Thailand when facing visa limitations?

Im trying to get the e-DTV for getting braces and havent found any clinics that will help with the letter/documentation. I have the rest of the documentation ready. I have written to several in Bankok, 1 with dtv info on their website and was told to come in and see the Dr first. I cannot enter Bangkok without the Visa to see the Dr. and If I got a 60 tourist visa I cannot then apply for the dtv from inside Thailand. Im also in process of selling my house so I cant buy a plane ticket yet as those take 30-45 days to close for the tousit visa eligibility. I'm 1 year from the 50 year old retirement age. I want to sell my house, get on a plane soon, get braces, visit the eye doctor, have a minor surgery that i should have had done years ago. All bringing the money into Thailand as they are wanting to do. To do this, I pretty much need to the get the DTV and will then apply for a retirement next year or as soon as I need to. Ive read a bunch of posts and pretty much been watching videos and reading about it for a couple months. Any insights to the dental route? im too beat up to do Muy thai now, Hoping by being retired in Thailand that I will get back in shape and go for that later. Thanks