T2W,
I still have not taken any pictures of my tank set-up yet, Sorry. I used a base plate from an RV store that normally sits on top of the tongue and mounted with angle brackets and some box aluminum to the skin, through the vertical beams and the structure of the horizontal beam of the floor.
I attached one piece of steel from up about 2 feet from the base plate down to the outside edge of the base plate for a little aditional support.
I can jump up and down on this thing and I weigh over 200#
The base plate has all the correct holes in it for the threaded rod that holds the twin tanks in place and for padlocks to lock the tanks away from a would be thief.
Then I covered the whole set-up with a twin tank plastic cover that you can also get from the RV store like this one...
http://www.campingworld.com/shopping/product/heavy-duty-propane-tank-covers/3953
A square box on the front of your trailer might be pushing your luck when it comes to jacknifing but this cover fits pretty tight to the bottles and my bumper/tailgate doesn't even come close.
You don't really need to hook up your trailer to your truck at a bad angle to find out how close it will come. Just use a 2X4 that is the same length as is the distance from your hitch to the side of the truck, then place the end of the board on the front of the trailer coupler and swing it around towars the area you want to mount the tanks. Nail another board to it at a 90* angle if your hitch is sticking a ways out from the truck and then put the shorter board on the coupler.
I hope this helps
