SETV has a 3 month validity and is good for a 60 day entry. If a SETV was issued 20 Jan and is valid until 19 April, does the 60 days run from date of issue or date of entry when you get the "used" stamp??
TLDR : Answer Summary
The 60-day validity of a Special Tourist Visa (SETV) starts from the date of entry into Thailand, not the date of issue. This means that once you enter Thailand and receive your "used" stamp, the 60 days of stay begins from that moment.