I see that I can fit one battery pack above the shelf and thread the cable through to the servo plug. I’ll do this with the 5 cell NiMH pack.
The second pack which I’ve seen described as “optional” isn’t really optional in normal use at all: I plan on using Bluetooth for any connection and not having my Hexy tethered to a computer, which I imagine is the common use case - in that case where is the second battery pack (4XAA) supposed to be positioned?