....favored m60 and e tanks....found the the m's a workhorse, just crank and breath, thankfully no thinking involved...
....the e's took a bit more "finagling" (a word my dad favored). as the volume dropped (especially below half) the lpm's would follow...i was constantly adjusting the flow upward to maintain adequate lpm. got to where i went by sound, as reading a stinking dial when being hit was not user friendly. in my case, it meant volume left was not a consideration and i used to leave a little in several tanks as a "reserve".....like a scuba diver. the horror movie scenario of a friday evening, empty tanks, and closed O2 shop being one you only wish to experience ONCE!.....