With the gaps as they are, an external AR ould do nothing. There never is a short for the AR to detect and fix.
Two thin continuous rings with insulation between them would work, but you may have to shift one of the bridge power contacts to make it touch one ring, while the other pickup would touch the second ring. You'd have to move one of the bridge track power wires to attach to the second ring. They both need to be continuous rings with no insulation on them for this to work - effectively wires right fromt eh bridge rails to the power supply - straight wires like that work, but if you constantly turn the table in one direction and never back they tend to get twisted up. Any insulation between a pair of rings has to be radially around the shaft. You can make the existing gap shorter as long as neither pickup can span both pieces (that would be a short) but I suspect it's already about as small a gap as can work reliably.
I'm pretty sure the track feeds are JUST track feeds. They have nothign to do with powerign the bridge motor or electronics. You can stop the table at the dead spots and then move it again - if the bridge track pickups also fed power to the bridge electronics the whole thing would stop and get stuck at the gap area.
This thread has more and more convinced me to not even bother with the Walthers built up turntable and instead just get something like the Diamond Scale kit or similar. I don't need indexing, I plan to have the turntable fairly up front where it will be easy to line by eye.