I don't drink alcohol at all and haven't for quite awhile, and my blood pressure is pretty low and hasn't changed significantly. I did try cutting out caffeine entirely for several months (and the tinnitus actually started when I wasn't haven't any caffeine at all).

I do very slightly grind my teeth in my sleep, but in this particular case the problem is basically solved (at least at the dental level) because I have mild sleep apnea so I sleep with a plastic mouthpiece every night anyway.

I'll look into the magnesium supplements.