I already know that there are to many variables but I'll ask anyway. If I were to use quality nylon (REI - EMS brands) cordage for a structual ridge line how much would it/could it stretch during an over night slumber? One inch, two inches?? Does any one shorten there ridge line knowing that it will hit the target length with in a certain time at max stretch? Am I over thinking this?

The only know factors are ENO double, 6' 175lbs occupant.