I have the BT7 Biotuner and it helped me greatly for anxiety attacks, Depression and insomnia. What it does is balance both sides of your brain. Personally for me, it helps to get myself out of my head, and think more objectively and positively. I have also been going for emdr therapy and find the biotuner a really good complement during the week.
I find setting # 1 good for repetitive worrying thoughts and # 3 good for focus, openness and a relaxed mind/body.
Setting # 2 (which is the .5 hz) is good for sleeping and I use that 40 minutes starting around 6 pm.
p.s Steve, you mentioned tapping while using the Biotuner
.. might work too to see what eye movement from left to right would do!