Correct me if I am wrong, but the whole idea of PC'ing the boolit is to get ALL the lead covered. If you use wires in the lube grooves, there is some shiny lead showing and that will possibly lead your gun barrel. Unless you are grease lubing the PC's boolit too. I use several methods (not recommending any specific method.....use your own choice) that insures the ENTIRE boolit is coated - including ALL the grease grooves, with the exception of the bottom.
bangerjim