Since the force of tieing something down pulls from side to side you would be creating a side force on the tiedown if it was facing forward. I have yet to run into an instance of the tiedown being an interference. I keep some 550 cord wrapped around the one on the right for securing my propane bottle when swapping it out. The tiedowns maybe stick out 3 inches. My cap has a toolbox on the drivers side so that side of the truck that sticks about a foot into the bed area. I'll see if I can get a pic looking directly into the back today.

 

I have two in the back like this, works great for me.

 

I just use a carabiner like this one to extend the area of the tie downs plus it lets me use a "truckers knot" without having to pull the rope all the way through. I also use them on the closed tie down loops that I have in the stake pockets. When I'm done, I can remove them and there are no holds in the truck. They are only a couple bucks a piece and well worth it.

 

I would be extremply careful using those above. They are extremely easy to break if used in the wrong spot. I had used one to help extend a tie down point and it ended up breaking and cutting my younger brothers hand.
Trav