Using your load bars (E-track decking bars) to protect the front of your box is a good idea. I think RichM was the one that said he keeps one at the rear of the box to keep fork lift drivers out until he's there. Maybe it was someone else.
I've toured a lot of FedEx White Glove trucks. Those folks carry a lot of load bars to secure the high-value freight they handle. I think I saw 12 in a straight truck once.
As far as I've seen, there is no standard way to carry them. Some put them in front, some in back. Some put them on the top row to keep them out of the way until needed. Some use tarp straps (those rubber straps with S hooks on the ends) to strap the bars vertically against the wall near the door, so they are handy when needed. Some line them up on the top row and stow floor decking on top of the bars.
My wife and I have experminted with a variety of ways. Currently we put them all on the lower level near the front, behind our freight handling equipment (pads, pallet jack, dollies, etc.). That makes it easy to walk over the top of them to get to our gear. It would also keep a fork lift from reaching the front. It also makes it easy for us to work with the bars when needed (we're short). If we get a load that fills the truck, we move the bars to higher rows if the bars are not used.
Our fleet owner stocks his truck with six E-track load bars. We'd like more and are planning on stocking our new C-unit with 12. There have been times when we would have liked to deck the freight. 12 bars would enable us to do that and secure the lower-level freight too.
We've learned to undo the load bars on the front and back of the skids before we let the fork lift in. That keeps the fork lift drivers from picking up a bar with the ends of the forks that stick out beyond a pallet.
One friend recently suggested that we ban forklifts from our truck alltogether and load and unload all freight ourselves. We're considering that and have tried it on a couple of recent stops. I worry less about the truck when I'm in there with a pallet jack than when a total stranger is in there with a fork lift. When you consider the holes a forklift can punch in your truck, keeping the forklifts out may not be a bad idea.