Unsure of dwell reading

[bytes311]

I just purchased a dwell meter and I'm trying to adjust my fuel mixture because it been tampered with in the past, however, I'm not exactly sure how to read it. I heard that it should fluctuate between ~30 and ~50 when the O2 sensor kicks in, but I just watched a YouTube video of someone adjusting their dwell with the same (or similar) meter, and his fluctuated around 20 and 30 on the bottom, 6 cyl scale. so now I'm not sure where mine is supposed to be.

Here is his video: https://youtu.be/MbE-2k4Cy4E

The first pic is where the needle sits before the O2 sensor kicks in. The second pic is what happens when I press on the full throttle switch.
20150525_114148.jpg

20150525_114205.jpg

Edit: Here is my dwell reading: http://youtu.be/FTUJCUIWFhg