On the drum note if your using a shared kit I thought it was expected that everything gets changed. At Drakes the difference between set ups can usually be great and it doesn't seem to cause too much problems...aslong as people take their stuff off sharpish what's the prob. It doesn't take that long to change between kits...we've changed a 5 piece set up with 6 cymbols, double bass, different snare and different hats to a 4 piece with 3 cybols pretty sharpish without any one getting pissed off as far as I know... As for lending equipment you gotta be carefull...beer always seems to be a problem out drummer had someone spill a pint over his snare which was pretty annoying for him...though he's had to problem lending cymbols to people like the Switchblades and Atom drummers...if I use someones amps I tend not to touch the settings unless really needed and if I do they go right back...aslong as they say that's cool...you can kind of tell what a person is going to be like with your stuff and aslong as you tell them straight...and if they do not do as you ask then turn it off and tell them where to go...