This has been my choice for a short while as well, but the CR-123As are definitely another world from the other Omicron and Persei batteries. Needs a special charger (that is a bit wonky to get the batteries in correctly), rattles a bit in the tubes (to no ill-effect other than fit/finish) and isn't part of the standard Persei arsenal (though people may be led to think it comes with the base purchase - I think D9V could be a bit more clear on that).
This does definitely give us a lower gear in the Persei transmission, and it's a mighty useful one!
exit - you're headed down a less-travelled road. This is a good thing in my experience!
Edit: *grumble*Iris*grumble*would*grumble*be*grumble*nice!*grumble*
Sorry, I didn't see this earlier.
Your CR-123A's don't fit?
My AW LiFePo4 RCR123's work great!
And they also fit in the Persei stock charger!
Maybe yours CR 123As are shorter than mine?
Mine do rattle a little bit in the Persei tube.
However since the spring in the tube has a little "give", what I do is seat the batteries slightly higher than I normally would, and it pushes down on the batteries just a little bit, just enough to get them to stay in place.
If you shake the assembled Persei around they won't move.
If I seat them as high as normal batteries, they will rattle. I didn't like that.
I still haven't gotten any 18350s yet so I couldnt put them in the photo to compare size. Have a 18650 and a SD card though!