how you wire the tower depends on which bar you want to hang the speakers on. i just went through this. the speakers that were already installed were mounted on the rear bar but the wires were routed out holes in the front bar. having clearance for my bimini was a priority so i really didn't have a choice. it was a real pita to get the wire from the front to the back. if i was starting from scratch i'd strongly consider routing the wires up the back bar. i know this would mean that a) you could never put your tower down or b) you'd have to add some type of connection point external to the tube. as my wires already went up the front leg, i chose to keep that orientation and just route the wire through the middle bar that connects the front and rear tube. there is a hole drilled in the front and back to allow the wire for the all around white light. it isn't very big and honestly i had a heck of a time just passing jacketed 14ga. if you enlarged the holes, you would have to remove the wire to the light first or it would be destroyed in the process.
here's my thread on this topic with some pictures and lots of good advice.