Denny, after a day or two (rarely) without tinnitus, it will come back while I sleep later in the night around 4 to 5 am. I'll notice it's back when I get up to urinate. The tinnitus returning after 4 am is common with some other people. It's pretty loud when I get up to use the bathroom and quiets down some when I shower, shave, and eat breakfast, only to return to a louder state after I'm at work.
Again, my hope is that we keep talking until someone figures out or gets lucky on breaking the cycle. If we all have days without tinnitus, there MUST be a way to replicate these days during days that we are "supposed" to have the tinnitus!
If a PhD would take one of us during a clinical trial and study us closely for several days during tinnitus and non-tinnitus days, I would think they could tell what the difference is while ruling out other possible factors. It just seems they don't really care that cyclical tinnitus exists or will take the time to take advantage of what it may be able to tell us!