I once read that if you want to tune down on the JP you need to setup the guitar again in order for the strings to stay in tune. I only want to tune down 1/2 step, and it will not be a permanent thing, so will I need to setup the guitar again?
you shouldnt need to, so long as you are not using super light strings. maybe some slight adjusting might need to happen, but not a whole setup. most gigs i do i have to tune to Eb, never have to adjust anything. I use my silo special and Luke or Y2D live.
You definitely won't need a full blown set-up. As a matter of fact, you will only need to make some very minor adjustments.
String it up and tune it to pitch and see what's happening.
I rarely ever have to do full blown set-ups on guitars after they are all properly set up to begin with.
I'm guessing you might have to do a very slight trem claw screw adjustment, and maybe a very slight truss rod tweak. Check your relief and you should be good to go.
Thanks for the replies. I only had to make slight adjustments to the truss rod and trem as you had expected. It plays just as well as before and the tuning is stable. Thanks again.