Great video, thanks! Where can I get one of those multimeters?
They are usually in stock here:
510 Ohm Meter Model 2 - Kidney Puncher
I vape a twisted 28g .6Ω micro coil all day everyday. When you go below .8 you just need to maintain your contacts more often. I have to file and noalox mine about once every week or so.
Below .6Ω your getting into button melting territory, but only if you do not diligently maintain your firing pin to prevent heat/arcing.
Below .4Ω you've crossed the threshold that will collapse your spring.