When I bought the tension gauge I had a heck of a time with it and about threw it away. I threaded through the pigtail, changed this that and the other and kept having to adjust tensions and pray....literally....as I was trying to get a Tajima TMEX-C1201 regulated as I had just bought it used. Still inconsistent, thought I just wasted money, etc. etc. etc.
Fast forward 6 months....
I decided to try it without threading through the pigtail, realized my tension was waaaaaay too low, adjusted the bobbin tension to 23 and the top tension to 120-130 and the machine has been working great ever since. If only Tajima website, SewManyParts (where I bought it), or someone else would have told me this when I got the gauge.......