Sorry, I didn't really understand the 1st little bit of your question so I'll just give you the "just" of the thermometers.
You should have atleast 2 thermometers with probes (those stick on thermometers are crap) You can get thermometers with probes for $10 so their cheap. Place one thermometer probe in the actuall warm side hide box as this is where your snake will spend most of their time, just tuck it under the edge of the hide so that it isn't in the snakes way. Place the second thermometer probe either in the cool side hide or in the cool side corner. Then I would get one of those thermometer/Hygro digital combos that also has a probe for tempature & humidity levals(you can get a really good one for under $20) Place that combo probe in the middle of your cage about half way up from the bottom so that you can keep a good eye on the ambient temp and humifity. If you do this your set.
If you don't have the money for the extra thermometer then use what you have now, just make sure that the one you have now with the probe is in the warm side hide box because that is the most important.