I pretty much did what you suggested. I used two short pieces of wood and drilled a hole in both and countersunk them so that I could pass a flush fitting bolt through, with its head being agains the wall. I then inserted the bolt so its thread was protruding away from the wall.
Then I attached the board to the wall by nailing it into the studs. Finally I used the mounting holes on the ends of the screen housing to pass the bolt threads through, put a nut on the end and viola. The only trick is making sure you measure the distance between the bolts correctly ESPECIALLY when installing the second board. Of course if you use one board you can do away with that aspect of it.
Hope that helps.
Then I attached the board to the wall by nailing it into the studs. Finally I used the mounting holes on the ends of the screen housing to pass the bolt threads through, put a nut on the end and viola. The only trick is making sure you measure the distance between the bolts correctly ESPECIALLY when installing the second board. Of course if you use one board you can do away with that aspect of it.
Hope that helps.