Running wiring from mast lights

I used the brass mast structure as an electrical common return to cut down on the amount of wires running down it. There are three lighting circuits on the main mast, steaming light, deck floods and fishing lights. Without using the mast as a common return, there would be 6 cables running down whereas I only have to have 3. A wire is soldered to the bottom of the mast and all four go through the whaleback and down the inside of one of the whaleback central supports. It is most important to ensure that the three positive wire cores have no contact with the mast otherwise you're in for lots of problems.  The navigation lights are manually switched from inside the fish hold but the deck and fishing lights are operated via a servo driven cam which has three microswitches to give various permutations of operation.