Not GP, but I also have a guitar tuned in fifths. A high `B` string wouldn't last 10 minutes... I've seen schemes that have a G there, I went for two CGDAAE, w

Not GP, but I also have a guitar tuned in fifths. A high `B` string wouldn't last 10 minutes... I've seen schemes that have a G there, I went for two CGDAAE, which is not too hard a change from the usual guitar tuning (though I ultimately dedicated a guitar to that tuning, as did the GP).