[suicideneil]

That sounds like the best idea, to run it for longer and see how high the temps climb; if the esc stays fairly cool then I would say try gearing up a tooth or 2 on the pinion, just to see if it makes any difference. The hacker c50 doesnt have as much torque as an XL motor, but would be about the same as an L, so provided the kv ratings are similar, I would expect the hacker to run slightly cooler than the 10L (because its more efficient).