Make sure it can move in 2 or more directions, it sucks if your bore gets stuck and the only way it can move is forward. Block Breakers need to be attached redstone tube frames, and each direction the bore can move needs to be covered in them, so compact bores are cheaper. Your going to need at least 4 enderchests, 1 attached to tube frames to bring the stuff to your base/processing plant, and another attached to a system to keep a bat box charged with blutric energy for your frame motors. The other 2 are the ones filling the batteries and being pulled from by your processing plant.
If you want to go very low tech, just attaching red alloy wire to the redstone tube frames and the motors and using a timer of 1 second will work. If you want your bore to be muli directional then build a circuit that lets you select which pair of motors get used. Use wireless redstone and build your circuit away from the bore, it will keep the size down.
Most importantly: Use covers everyplace except where you need panels for wiring or other blocks.
