Its ETB for Emerald Tree Boa, not GTB.
As for the placement it is the same principle for both ways. My way is cleaner looking and keeps the probe in the direct path of heat. Your way leaves a probe dangling on the side and I don't like that. It doesn't look finished to me. I use rhp's for both terrestrial and arboreal cages(gtp, blood, brb). My Blood Python is much thicker than a few inches and trying to dangle the probe in her cage would leave her leaning on it and blocking it or have it to high up the wall. I use the same mounting method in both types of cages and it works great. My BRB had a really dressed out cage with fake and real plants, logs, hides, and soaking tub. If I tried to use the dangle technique the back wall was shielded by all the décor and the only good way to do it was to use my method. Doing it that way gave me just what I needed.
As I said the principle and the procedure to dial them in is the same and it requires a temp gun. The only real difference is how it looks. People do things different to get the same results but I don't like how you try to tell others my advice is not going to be correct for their application when it is. Im not guessing here as I do it so I know from experience.