I will assume they are the same thickness?
As long as they are solid all around should work fine.
I would also if there is room redirect your motor signal wires
through the same channels as you did for the motor power wires.
Then feed them up and out of the slots forward and aft of the KK2 board.
The only reason I suggest this now is when I 1st built mine I too brought the wires above
and then after 2 or 3 rebuilds trying to clean things up I just said the heck with it
and redirected as much of the wires I could under the top plate
and brought them out nearest the areas needed.
Only thing I would think might get in the way is how thick those spacers are
if they will give you enough lead way.
As you keep tinkering you will find your going to have that thing apart
more then in the air at first....at least I know I did
I recently had a 3D printer guy blast out some Spacers for the arms which are thick enough
to give nice room between the top and bottom plates for the "dirty" side of things
They also provide a nice size slot to run all of the wires through via the arm area.
These are the ones I had printed in black. I did not use the LED holder since I made my own.
http://www.thingiverse.com/thing:473966
