In reply to ow arm:
Yep - I'm another one of those with a very precise system that has worked well for me for the last ten years or so. 4 racking krabs for standard nuts (all Rocks in my case). 10,9,8,7 / 9,8,7,6,5 / 6,5,5,4,4,3 / 4,3,3,2,2,1,1. And one racking krab for brass offset micros (which overlap Rocks 1 and 2). This way I equalise the weights on each krab. I also have sufficient overlap that I'm unlikely to pick the wrong rack for the crack I'm staring at and if I drop a rack I've still got at least one full set (as long as I haven't placed too many runners by then of course).
My racking krabs are DMM featherlights from the 80's. Still one of the lightest krabs around, but pulled by the manufacturer (as I understand it) for not passing gate open tests in the late 80's and definitely only psychological if I had to use one now - they stay on the harness!