The advice is always the same. If you need to ask the question, you don't know enough to undertake a DIY hanging. Call in the experts, and there are a number of good reasons why:
Safety - Get it wrong and someone will be injured, or maybe killed
Liability - Especially in the USA, you may be held responsible and sued for zillions of dollars.
Freedom - If you do a job shown to be negligent you will probably be charged with manslaughter, and probably do time in jail.
This is theatre, we are in the entertainments business. This stuff is about illusion and make believe. Lets keep it this way. No show is so important that someone need to die for it. Never, ever put a proper rope round anyones neck.