Reply to "How do i wire toggle a switch in to control power to a siding."

I would definitely isolate the two loops with gaps between the x-overs. This will help out later down the road if you decide to add a second TPC. With the TPC you can run conventional engines or even MTH engines in conventional if you decide to. 

From an operational standpoint I would swap the the two x-overs putting the pair at the top of the diagram at the bottom and bottom set at the top. This will give you more operating freedom when doing switching on the inner loop.