Current scenario. If you have enough troops to place 8's on all of your border tiles and have leftover troops, the game spawns them randomly all over the board.
Suggested scenario. Auto-spawning them as most would do in such a scenario - reinforce a second layer of borders and after that a 3rd layer. I think that would be more efficient, no?
P.S. Also, the hardcore border placement could focus more on the high values, rather then spread out. For instance putting a 5 in front of a 7 is quite worthless. Sometimes such placement makes more holes, than plugs. Can anything be done in the sense of programming?