Yes, you can set up two, but probably only need one.Your boiler has a gauge, so I would just put the sensor on the basement.
It will not be as accurate on the per as on metal. I tried all the different variations.
The best is to do it as I said above on the heat exchanger copper pipe on the side of the water tank. That is the first hook up as the water comes in the house.
Once you gauge your temperature drop from the boiler to the house it will probably not change, so you could just use one probe in the basement.
My lines are 9 feet deep, and I don't have any temp drop over 120 feet. So, I don't bother with two probes.
Also, don't put the sensor outside on the boiler. When it looses signal and sync you'll have to go outside and re-sync it.
It works great in the basement. I never have to reset it.
I hope this question isn't too obvious, but, there are two sensors, right? One for the "meat" and one for the "oven"? So I could monitor two lines with one setup?
Has anyone strapped the sensors to pex?