Fifty plus years ago I worked for an electronic organ manufacturer. They used Ne-2's by the thousands for their oscillators and frequency dividers.
They burnt in the lamps for 5 days. Been a while but as I remember it was about a 30 foot long wall, with maybe 12 rows of vertical pairs of clips, spaced every inch or so along the entire length of that wall, about 4500 bulbs at a crack as I recall.
The bulbs were then harvested according to their "firing" voltage. Don't remember the voltage increments or the entire range of voltages, but there were several different grades. The bulbs were then used in pairs of the same grade. Interesting little devices. Here is a little more information, maybe even more than you want.
http://www.tubebooks.org/tubedata/glowlamp.pdf
