I've currently got D-Boys covers on my rails and will be running a wire coil down from a light to a pressure switch. Anyone have closeup pictures of how they successfully mounted wires? Thanks.

I don't use rail covers myself, as I find the feel of the rifle with them is too bulky for me. Also, to me, the uncovered rails feel good and are the best grip surface I could imagine. Because of this I don't know if what I did would work when running the covers, but here goes.
I have both a laser and a light mounted forward on my gun. I ran the pressure switch wires into the vent holes near these and snaked them along under the hand guard to have them surface through a vent hole near where my hand grasps the hand guard. I then used the double sided tape they come with to mount them down in the recesses between the mounting rails. Then I used black tie wraps routed through the vent holes to act as a backup to the double sided tape. The pressure pads are mounted where my fingers naturally rest. They are out of the way, as are the wires, yet are immediately accessible when I need them. I wish I could post a pix. but I an not a techie and don't know how. Hope this helps.