You can run without full buckets. First, DONT CHOP THE NICE ORIGINAL BUCKETS. Second, go find a RRC and take the buckets out of it. The have no backs already.
All lights seem to be about the same depth to me other than, as you mention, LEDs. I have seen right angle plugs which might help a bit (or just use three individual tabs rather than the full plug).
*not legal advice*