Kyuss' Tuning with a 5 String

[el-Supremo]

I noticed that alot of Kyuss' work is done in C F A# D# but I was wondering what the B string on a fiver would be tuned down to. I wanna be able to work the lower register of the five into the songs in a consistent manner. Any ideas on what would be a suitable pitch to tune to? My apologies if this is in the wrong section,

[()smoke()]

I'd just play the 5 in standard tuning, but if I wanted to facilitate open low string usage, I'd just just tune it up to C rather than down...

[ourworldisgrey]

Just tune every string up a half step.