Loni,
Agree about the GridLock.
I learned something very useful last week at the AAR class
from Stephanie Schiller and Jeff Hunt. When belaying a second off the anchor
with ATC Guide / Petzl Reverso 3 / etc. in auto block mode, using a
carabiner like the original Petzl Attaché Screw Lock helps
significantly. For the carabineer that the rope runs over, the round
cross section shape of this carabineer really helps with the rope
friction. Easier to pull in rope. Petzl still makes them, and Pro Mountain
Sports has them in stock. Thanks Steph and Jeff.