1 - most offices make you take the 30 day regular extension first before you can apply for a 60 day covid extension
2 - you can get ONE 30 day extension on a visa exempt entry
3 - in bangkok you can apply for an extension when you have 45 days or less left on your current entry stamp (meaning any time you want to now) There is no 'waste' days because the 30 day extension is added to the expiration date of your current stamp
4 - nope
5 - in bangkok you have ONE CHOICE as far as where you go to extend a 45 day visa exempt entry and that's out at the Muang Thong Thani Immigration office here
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