I'm a long wall fan myself and my understanding is that it is definitely the way to go with Dunlavys. theonly note of caution I would sound is that, with 12 feet total, you will have to place the speakers very close to the wall benind them (and you very close to the wall in front) in order to get enough distance between listener and speaker (8' is probably minimum).
Long wall vs, short wall
I am contemplating buying a pair of Dunlavy SC IVa speakers. My room is rather long (26 ft.) and narrow (12 ft.) and the ceiling is stepped (font half 7 ft. 3 in.. second half 8 ft. 2in.) the door is on one side wall towards the rear. There are two small windows in the rear half of the room on the other side. For all practical purposes, it would be impossible to have the speakers on the long wall. How well would these DSL speakers work firing down the length of the room? All other factors being otherwise equal would Thiel CS 6s work better in this room. Thanks.