Those do sound like a 1/8 BSPP. There are some nice digital gages made now that are way more accurate and let you track air pressure usage and spreads.
YesI did the conversion. It turned out great. I can fill to the exact pressure every time. Plus it makes it very easy to see what pressure my fastest fps shot is. I fill to just under that pressure and get 3 shots with a tight average.
Yes. I did notch it. I sent a pix. Dont know where it went. I will try again.