I tried every imaginable heating device (torches, bics, candles, matches, homemade electric heating coils, heat guns, etc).

Dremel heat gun is the best. You would not even need a GVG. It can vaporize changa or straight spice from anything.

It is simply impossible to overheat the spice, let alone to burn it.

No experience is needed. It does not heat too much to ignite anything if dropped and it stops wokring once dropped.