I am thinking of keeping my SG in half step down tuning once i get my LP. would i need to adjust my truss rod?
Doubt it. Half step isnt too drastic. I keep my Strat in Eb all the time.
Probably not. You should at least be able to go down 1 step, or more.
I move my tuning all the time from C up to E and I don't need any adjustment.
^ yep agreed. shouldn't make enough difference. there will be less string tension so if anything the neck will go a bit concave, if you notice that the action is a bit lower half way up the neck then maybe you should loosen the truss rod a tad, but i doubt that it will be noticeable.
Ok, thanks for the input everyone!