So for example when I would order my rack from EZrackbuilder or some other site the placement would be shown here imagine other ribbons around it.
Somethiong like this (From EZRackbuilder.com) This is where you can definately get the Placement and order of precedence correct if you don't want to go read the regulation. Also to make things easier if you are assembling it yourself (instead of just ordering a complete rack from one of these sites, you should be able to order 3 OLC's attached together so you are not trying to get them all to lay just right on the ribbon when you poke them through.