AW are imo the only
batteries worth using in smaller than 18650 size. Out of curiosity, why don't you go bigger? You've got to be swapping
batteries like mad, not to mention I seriously hope you aren't going lower than 0.8 ohm. I carry one spare 18650 in my flashlight, and that will get me through 2 days if i'm above 0.5 ohm.
The pisces (and clone) mechanicals are smaller than your average mech. 18490 mode is as large as most other 18350 mods. 18650 mode is about 3/4 of an inch shorter than a nemesis in the same battery.