Guitarists: here's something that causes me no end of aggro during performance - changing the capo setting between songs. It always necessitates retuning. This is, obviously, because the capo depresses the strings between the frets and, to that extent, stretches them. Because they are thicker, and therefore get pressed down harder by the capo, the bass strings are the most affected. Over the years I have settled on a brass Schubb capo and I use Martin strings. I also start a set by tuning accurately for the capo setting I'll be using first. But I hate playing fractionally out of tune, and I hate making an audience wait while I fuss with retuning. Any ideas?