Hi again, I have been very please with where i put mine on the
back i think you do lose some heat out the glass but you have a nice heater and this wont be a problem. I prefer the look of the tank with the heater on the back and you get much better feng shui.
Its up to you i am sure there are people on here which prefer one way to another but its not something to worry about.
The probe is placed in the middle and just off the ground I have coilled my into a vine so you cant see it.