first, yes you need a proportioning valve but as this picture shows, it is not mounted. For appearance purposes mount the valve to the side of your inner fender. Secondly, yes the valve on top is for a light, but most don't use them. Next, after measuring your line from the MC to your valve and from the proportioning valve to both front and rear wheels, head to NAPA. They have them in many sizes already with the threaded nuts attached. you can bend them with the tools as shown and when you get to the front wheels and to the rear wheels, you can measure and buy a length a bit longer than needed and put slight bends to the lines (to reduce the overall length) so they fit from fitting to fitting, this will work perfectly for you. I actually bought mine from NAPA and had pipe laying around that I bent mine over and they look good.
