So at work my system for setting usually consists ascending up one rope (grigri + ascender w pulley = 2:1), and having a few asana setters buckets filled with holds attached to a WC ropeman on the rope of the route next to me which are hauled up as I move up. We mainly use T-wrenches which are untethered while setting.
The area at the base of the wall I'm setting is sectioned off with rope to keep people from walking under me.
This system allows me to try sequences while setting easily and move up and down quickly. However it doesn't offer much in the way of avoidance of dropping things.
At the top of the walls, its 60ft to the ground and a wrench, bolt, or god forbid a finishing jug, falling from that height would do some serious damage to someone. And the safety area roped off wouldn't be much good if there was any outward force on whatevers been dropped. I've been fortunate enough to never have dropped a hold or anything, but there are many chances to while setting, especially in the summer when my hands get sweaty. Wrenches get slick, holds get slick.
I've started using a tethered ratchet for setting now which I prefer, but the t-wrench is still common practice. We try and do all the setting early in the day when there are less climbers around, but we're open from 6am-11pm so there is almost always someone at the gym.
So my question is, which method do you employ to keep yourself, and the climbers at your gym safe.
Do you have some complex safety system? or rely on steady hands?