This is where I bought mine, back in 2017: Page Not Found - Aliexpress.com (they are still there, just follow the link).
The runtimes will probably be a bit better than the Tool AA (with Nichia), but just because the Osram Led is more efficient. If you have a Tool AA with another LED, I can’t be sure about efficiency/runtime.
Check zeroair.org or 1lumen.com to see if they have reviews on that.
To take the TIR Optic from the EDC15 and put it into the Tool AA , you need some pointy tweezers that whose tips fit into the small holes in the driver’s back. Then rotate clockwise to unscrew and counter clockwise to screw the pill again.
Check my video, minute 9m30s: https://www.youtube.com/watch?v=Ge3kGRdlEtI&t=69s&ab_channel=MascaratumBLF
Then you just need to take the TIR out and put it on the head of the Tool AA, and screw the pills again. Always be careful and make sure that the TIR opening is not damaging the LED.
I hope this helps in some way.
There is also another light you can check, although…I am not sure if you’d like it: the DQG Slim Ti AA (you need to buy the light and the extension tube, if you can find it): This is my review of it: “REVIEW”: DQG Slim Ti (1/2 AA and other batteries) ***[DISCOUNT CODE ADDED - 05/22/2018]***
It takes AA and 14500, it is not brighter than 600 lumens, it has 3 modes, always starts on the lowest mode, and has reverse clicky switch, so, no parasitic draining.
It is lightweight. I never did runtime test with it, so I can’t be sure how long it lasts. I do know that when using 14500s on max, it gets hot, since the driver and the LED are all in 1 board. Also, the flashlight is quite thin, so heat dissipation is quite…nhe… But it is one of the smallest AA/14500 lights you’ll find!