rolled 5, 5, 2 = 12
Well, in my eyes, the Warp-Engines would be, like all the ship, huge beyond reasoning. The Eldar are put there, alone. No humans with them. They are barely ever contacted, and never bugged by any official sanction of the Imperium. They are still fighting the Dark Eldar, and all the rest. Just now they have an additional task, the maintenance of the Engines. Additionally, the engines themselves may not be an inertial force, but rather, the "exhaust" of the anti-warp presence. Instead of pushing the warp aside constantly, it's funneled, and creates a inertia in the WARP. Sorta like pushing the same cart, in two dimensions. The Anti-Warp properties would hold a ship in place if it's that big, the warp engines make that side of the equation move. Just as the regular engines do the job of moving it through real space.