Sounds pretty good, glad Bob had the 6.1 as I remember he was NOT happy until he got the new truck. Check into the air bags or Timbrens, I'm sure you'll need them. Next time you're out in the des. look at the straps under Bob's tanks, mine were supported at the top like you describe but also had straps/angles under them. Since this is a newer rig they may have upgraded the supports, just don't want the tank falling out while going down Bessimer!
Good info there, ours had upper and lower supports, the lowers were thin angle iron and bowed pretty good when filled, which put a load on the Head of those little sheet metal screws, which would make them break the head off the screws or strip out the holes, I fixed ours before any damage, The guys over ay RV net had told me about this problem as well as the floor being a problem. It will get repaired with some plywood instead of that junk particle board.
Good luck with the trade Chris
I am sure you will be happy with the Rig, we have looked at them , we want to go to a 5 er, the bed in our tag trailer is a pain to say the least!! Someone gets to climb over the other in the middle of the night when needing to use the the rest room, usually DW, but after a few beers around the campfire