Changing from a lowB to a highC...

you might not have to turn the truss rod at all, but check the sticky at the top of the page that will link you to gary willis' site, its got a great tutorial on setting your truss rod as well as a walkthrough of a whole setup.

 

Been there, done that
Change the strings over, let the bass settle overnight and have a look at it in the morning. If it's got too much relief you need to tighten the truss-rod (righty-tighty, lefty-loosey). I'd give it a 1/8 turn, then let it settle for a few hours. Repeat as necessary.

BTW, I'm quite partial to Red Stripe - shame we don't get it here in Oz. The ads are great too

 

I would just do it, and then see if it needs anything the next day or two.
Don't anticipate it, just react and adjust.

 

Agreed, don't make the change unless you have to.


If it aint broke, don't fix it.



On some basses, the neck stays the same for this switch. I personally had to loosen the TR (I think I took too long restringing and it backbowed a little).

In my experience with switching to this tuning though (and from what I've heard from pretty much anyone else who's done it), you will need to redo your action and intonation.

 

The neck usually responds to the higher tension of the C vs. the B strings, so you may or may not need to tighten the truss rod. It depends on how much it moves and how fussy you are!

The intonation will need to be tweaked, but get the relief and string heights dialed in and save the intonation for last. Give yourself a treat and raise the pickups a hair as well. That C string can kind of disappear if the pickups are too far away.