Hi,
I can't speak to the blood python bits as I have never kept one. But I can maybe help with the equipment questions?
We generally do not use the adhesive on the heatmats themselves to attatch them as it makes removing them etc a right royal pain in the rear - we normally just stick them to the outside bottom of the tank with foil tape. Foil tape is also what we recommend to stick the thermostat probe to the surface of the heat mat before doing this.
Heat mats do not raise ambient air temps at all.
The temps you want for a blood should not feel hot to your hand in any case - what do the thermometers tell you the temp is?
What are you using to control the heat mat? Have you checked it is working (using a lamp for example ) and have you tried plugging the heat mat directly into the wall to see if it is working (not while the snake is in there obviously ).
Thermometers do indeed have a "refresh rate" - it's generally under 30 seconds or so though rather than a couple of minutes. But either way when making changes to thermostats etc you need to wait at least an hour most of the time ( and often far longer ) for the temps to stabilise.
This is why people like temp guns - they are prety much point and shoot for instantaneous temps. That and they are amazing fun to chase cats with.
dr del