Bigger Batteries

[Mineral]

I have room inside my hilt (an old three D-cell flash-gun) for 26650 or even 32650 3.7V (protected) Li-Ion batteries. Some of the options list capacities of 6000mAh or more. Other than the usual caveats that go with "-fire" Chinese Lithium batteries, any reason these wouldn't be a good idea?
Would I be better off with three 18650s in a parallel triangle-pack arrangement?
My reason for wanting such a big battery (or battery pack) is: it would be functional as both a nice long-lasting power source and a good heavy counterweight if I can mount it toward the "pommel" end (and a forward facing speaker). I'm actually thinking of a way to make the battery just slide in and out of the hilt using the original screw on battery cap; no CC obviously.

[rlobrecht]

I can't answer your questions, but 6000 mAh sounds awesome. All day use without a recharge!