Update..
Got the two more pens a couple days ago, and finally got around to testing them out today.
For lack of AAA's I used a single 10440 with a spacer instead the regular AAA's so obviously the voltage is somewhat higher... ~3.7 vs ~3.0.
Tested all three pens, including the original I got last time.
Original pen hit hit ~30mW very quickly than plateaued for about 15 seconds... after which it went up to a pretty impressive peak of 59mW, and stabilized at around 50mW, starting to drop off after 1:20. This pen has a weird tendency to pulse at times, but it does work just fine.
Onto the new pens...
One was lackluster although perfectly in spec. Hit 31mW, evened out at ~28mW and stayed there. Very stable.
The second one blew me away. Hit a peak of 71mW
I tested it three times just to make sure... and all peaks were around 70mW. It doesn't stay there for too long, but the downward curve is slow and very even.
Three pens so far, and all are very good:beer: