Sorry for the obviously late reply. I just saw this thread.
HERE is what I did.
I strongly recommend that you have some way to make the arm mounted TV TOTALLY immobile during travel.
That arm is designed to hold the TV in a single position. It is NOT designed to be constantly moved from a "stowed" position to a "viewing" position. The pivots in the arm joints are not designed for frequent movement. I can almost guarantee that vibration and shock will cause one of your arm joints to come apart.
As part of my design, I have a shelf with a tie down clamp. Even with that precaution, the center arm joint came apart and the TV came off of the shelf, bounced off the couch, and landed face down on the floor.
I have installed Bellville spring washers into the arm joints and Loc-Tited all of the arm hardware. The Bellville washers provide a constant compression on the joint hardware and allow very stiff movement of the arm from the traveling positon to the viewing position. Even with all that, the arm joints STILL come loose while traveling.
I agree with putting the mounting bolts all the way through the wall. I don't think that your threaded lag screws have "stuff" to hold your TV while moving. All it takes is one pothole to make your 9 pound TV into a 20-30 pound weight.
I also do not think that your tie down straps will be tight enough to keep the TV from moving while under way. ANY movement will cause things to come apart.
After watching and before we travel, with the TV stowed, I reach behind the TV with a LONG allen wrench and tighten all of the arm joint bolts.
Just watch your installation VERY carefully until you know how it will react while traveling.
PLEASE let us know how it works out.