If you build the RSA balanced, I would recommend trying to build it without the normal angled bracket. On the LC, the angled / cable goes right across the volume and it is a tight fit. For the SR-71B, the volume is to the left but on the LC it is on the right.
Here is something you don't see every day. 64 Audio has the U10 on Amazon for $1100 compared to their website which shows a price of $1399.
That is a pretty good savings. The Amazon item though didn't become available until June 13, 2016.
I would suggest calling 64 Audio and talk with Isabel or Alex about your burrs and the chip. I would think they would not hesitate to have you return your A12s to correct the problem. However, that would mean being without them for a week or so.