The back channel of the print allows for wiring
The battery clips in nicely to the print and holds it well, just need to tweak the alignment.
The spark 2 fits, some modification for ease of wiring is needed.
I will need to drill out part of the grenade section to allow for the the charge port under the rear hole in the clamp section, I might change to a smaller recharge port also.
Already on to the upgrades . . . .