The sleep test will definitively determine if the fit is too tight or not. You should wear the inner wear alone and see if you can sleep thru the morning wood without being woken up by any discomfort.
There is absolutely no danger here as your penis will be fully engorged with fresh blood. In my experience you will just end up pulling it off and going back to sleep without fully waking up.
When properly fitted you will sleep soundly and then after the material has broken-in for a more comfortable fit you can even layer one of the spandex sleeves and wear the Retainer band as well.
With experience you will know how to optimumize your set-ups to get the best performance.
The sleeve materials were selected from a wide variety of samples to find the ones that did not fray. The fuzz that you see forming is at the cut ends of the thread only. You can carefully trim the fuzz off with a sharp pair of scissors for a clean finish nice again. After you do this 2-3 times the fuzz will no longer appear.
We tried various methods of sewing an edge but the finish is not so nice and more importantly the function was compromised.