There's a cutoff knob on the CR-70. You're supposed to turn it till the needle sits in the cutoff area, then read emission. With a gassy tube there is no getting it to sit in the cutoff region, because as soon as it reaches a certain point it will go right to full conduction and peg the needle. That's the gas regulator action I was talking about- full on or full off is all you get. Yes, my tube had a purple neck glow that s typical of gas.
This is what it looks like on a 15GP22:
It's not that glass to metal is a problem, there are NO MORE tube rebuilders in the USA. Until ETF gets their stuff up and running, we're all sitting on a pile of useless tubes.