I was at Takhli in 1966, with the 333rd also a aircraft mechanic. The Checo Report verifies herbicide spraying around Thailand based for defense purposes. US Army Field Manual 3-3 covers herbicide spraying and drift area, see section 5 chapter 5 last paragraph about 500 meter drift zone. End of runway, trim pad and munitions storage (where start cartridges were stored) are all in the drift zone. Do you homework, lots of good info out there, you need to prove you were on or near the perimeter at Takhli. I used the Takhli base map on this site and hand colored the drift zone on it. If you need more help let's us know, we've been there too!