I have a clutch that has just started hatching after 70 days.
Not sure who was responsible for first recommending cutting eggs pre-emptively, but, they gave devastatingly bad advice to others in the hobby. I don't respect any breeder that cuts eggs before first pip.
Cut at great risk. Take a pair of scissors and wipe the blades with 70% Isopropyl Alcohol and make sure you air dry them (do not touch them). Wash your hands with soap and water and then pinch the top part of the egg so that you can squeeze it together and ensure the snake will not be injured, then make a 0.5" (~1.3cm) incision on the folded section. Your goal is not to cut the snake out of the egg, but, to provide them a means to reach more oxygen and gain the strength to push their way out.