this is what i did, I got all my servos lined up with the holes in the hatch, then took out the left ail servo, so i could squeeze the rec thru the tray, then i plugged all my stuff into the rec, before shoveing it foward of the spar, wedged it up in the leading edge t with some foam, then put the aileron servo back in. If i was building this kit, i always make my hatch in the top of the wing, and mount the servos into some hardwood that I mount to the wing sheeting. (bottom of the wing)
this give you a littl more room to move around in these tight compartments and it works pretty good.
In my knife ARF have the rec in the left wing panel...........
and a 700nah battery pack in the right wing behind the servo tray


Good luck...G