I have an Air Conception and they say only to run e-props. Inside my manual, the torque specs for the prop bolts are 10 Newton Meters. Make sure your torque wrench is set to the proper setting and you should be fine. Go slow, and if you hear anything like cracking stop. And make sure you tighten them using a star pattern like you would a car tire.
I have an Adventure paramotor and the manual calls for 10-12 nm. However, I tighten them with a small Allen wrench and just go by feel most of the time. The important part is to try to keep the torque reasonably the same if not using a torque wrench. Hold the wrench in your hand the same way while tightening the bolts and it’s pretty easy to keep consistent.