Ok, so I borrowed a volt meter from a friend to reduce the overclocking on my rig, but I have a question for those that have made adjustments (this is a v3 rig, so has the v2.2 H-boards).
Do you adjust the trimpot while the rig is powered up but not mining? Or do you power everything down, make an guess at how far to adjust the trimpot, then power it back on to measure and see if you guessed right, and then repeat?
I always adjust voltage (either with a pencil on the older boards or with the trimpot on newer ones) while powered but not hashing. It might be a bad idea, but it hasn't caused me any problems.