Tightness of cervical collar and effectiveness? How tight should it be?

[CorruptAlligator]

I wear a soft cervical collar every night to supplement my therapy because I notice it helps bring down flow limitations.  

After wearing them for awhile, I noticed inconsistencies in the flow limitations.  Sometimes it would shoot up, and other times down.  

I was wondering what was the cause of such inconsistencies, and thought perhaps it's the way I tighten the collar.  

I notice that if I have the collar too tight it does feel like breathing is harder.  I think perhaps it's putting pressure on the neck when lying down with the head on the pillow, and perhaps work negatively against easy flow.

According to wiki, the collar can be tightened enough to insert two fingers, but how ever much you tighten, you can still insert two fingers on a soft collar. lol.  So, this is confusing on my end.  How tight should a collar be?

So, I tried loosening my cervical collar, and it seems to be helping with flow limitations.  I definitely think the height of the collar is important, but also it shouldn't be overtightened. Slightly loose seems to work better on my end.

What do you guys think?  Have you noticed anything like this?  Maybe this is just a coincidence I noticed.  

Also, how tight should a collar be?

[SideSleeper]

I've worn a soft collar for several years and I don't wear it too tight. I actually don't do the finger measurement, but if it is comfortable it is probably OK. I've never left it too tight--don't like the feel--so don't know if flow limitations are changed.