I usually cope with the C/drop C tuning by tuning my low B one semitone, up to C, on a 5 string, with all other strings in standard tuning. I've grown used to it, can play, say, most Black Stone Cherry songs like that. I also tend to play Kiss material (tuned D#) with the same overal idea, by detuning just my E down to D#. It's the most practical thing to do (ocasionally and just for fun) when I really don't use such tunnings for real life. If it was to be a permanent thing for a certain project, I'd definitely think of setting up a 4 string to the C/drop C tuning the rest of the band was using.