Have you ever seen Simpson's tune-up and setup routine? He brings ONE guitar, ONE banjo and his own minimixer with just a line feed to the desk and it still takes AN HOUR - leaving the other bands on the roster no soundcheck time at all.

Personally I think tuning into open tunings is easier than getting back to standard, and particularly on guitars with light-ish tops when if you tune one string you then have to tune the other 5 because things have flexed (until you decide to have a bridge doctor put in).

And I'm intrinsically suspicious of people who go on about the difference between F# and Gb, unless they audibly play the old scales.