I use the B-52 for multipitch routes, I also contacted Trango about some of these same questions I had myself.
If you're only using a single rope, you can hang the B-52 on the anchor using a single LOCKING biner, or two
identical non-locking biners with gates opposed.
If you have rope through both slots, then you should use two biners. Trango tech rep told me the important thing is that the B-52 should be hanging straight, free from jamming again rocks and other gear. The two biners should be identical, at least in length. But they do not have to be locking biners, non-lockers are ok if you oppose the gates.
Actually, in Trango's instructional sheet they do not show a diagram for belaying two seconds.