Spend a good deal of time fitting brackets upon which to mount the speedos (ESCs) before going for the keep-it-simple solution and gorilla-taping them to the sides, with a side order of cable-ties. This is assisted to an extent by the fact that they are the same depth as the sides of the airframe, and include cooling fins that match precisely the width of said ties too.
As to the battery-packs, I'd set my heart upon suspending them beneath the centre-section before opting for a more practical solution with a view to both operational procedures and maintenance. Among my golden rules is one stating that all motors and propellers should be fitted right-way up, and that all else should be fitted topside whenever possible. Dare to be different, my friends...
For the cognoscenti the packs are 22000 milli-amp-hour LiPo sporting six cells apiece. And can you spot from this view of the airframe the plastic nubs for locating the seat in place? Well done!
And now I'm off for a run... I deserve it, don't you think?