I currently have obnoxious bright red sides and a green mohawk with my dark roots coming in on it so it is like red, green, AND black. looks pretty awesome I think.
24 inches is the guiness world book of records. rawknthehawk is the guys screenname on here who holds the record, but he says its up to 28inches already.
I spray whatever color reads mohawksrock.com the easiest in the side. =)