I'm quoting a wall rebuild: 175 x 4. Middle section (50') has failed. Surcharge behind this Allan Block wall. No grid, and backfilled with sand/gravel. No drain field or tile. So, on a wall of this length, how would you guys vent the drain? Do you think it would be beneficial to vent the drain at more locations than just the ends? Only probably being, if I were to vent it in the middle somewhere, base course/drain is below grade? Just kind of thinking out loud. Any thoughts?