Welcome to the forum and the wonderful world of snake keeping!!
Just throwing this out there to try to help you moving forward...
Seperate your thoughts into paragraphs. It make reading your threads much easier, there for will often lead to more people reading and in return, more replies.
Now to help you out:
- definitely rely on the digital thermometer/hygrometers. You might as well just ditch the analog. As you can already tell, they are wildly inaccurate. It's like using a Fisher Price doctors kit to check a child's temperature.
- get those ambient temps up! After spending "a lot of time researching" you should have already known this, but let's just move on...
Your UTH is there solely to provide a hot spot to aid in digestion and not for ambient temps. Since you don't want your temps dropping below 75 you'll need an additional heat source. Whether you go with a CHE or bulbs you will need to regulate the heat source with an additional t-stat.
Also keep in mind this additional heat source will drastically drop your humidity, so be prepared for that.
Other than that, sounds like you're on the right track.
Good luck and feel free to ask any more questions you may have.