You need to get a temp gun. GTP and ETB are more delicate than many snakes and knowing what the real felt temps of each perch is important.
Im not there so I cant know for sure but my first impression is that the temps may be a bit low. ETB are said to not use their hotspot often but one should still be available. This spot should be 85-90 and some keep them as high as 93. Without a temp gun you are only guessing what the hotspot is in your cage.
If it were me Id boost the ambient temps a bit and get a temp gun a.s.a.p. They are fairly cheap on Amazon but if you are able Id go to a hardware store and get one today.
You should be able to insulate the back and sides of the cage to raise the ambient temps. Ive used thick art paper on my glass tanks to do this. It raised my temps a couple degrees.
It is also very important to get the temp gun so that as you are raising the temps you can check each perch and make sure they are safe.