I would doubt you would get sufficient amp draw for ‘half-decent’ brightness.
I think the direct drive 3xAAA LED Lensers only manage around 150 lumens, though I’m sure more would be possible with a decent driver.
Yes indeed a 3 x AAA holder that puts them in series is needed, tthogh I have a bunch of those holders and bought a bunch separately, all are series, di not see a parallel.
And as far as brightness go, when I put two holders wth crappy rechargeable AAA cells in my Thorfire S70 (thus using 6 cells) it was shining really bright, just very short. I like this, it is easy to see how a flashlight behaves on low power fast while testing them (I buy a lot of lights that have space for these holders, nice safe gifts)
Three more days…
THREE MORE DAYS!!!
Even my wife wants to hold this pilot approved flashlight three more days and then the real ordeal, NOT checking shipping status