First off, you mean 43 MM offset vs. 40 MM offset. Fork rake (offset) is the distence from the steering axis of the fork to the center of the wheel, measure at a right angle to the steering axis. The head angle is measured in degrees, not the offset.
With a large frame, steep head angle and corresponding short fork offset, there may be some toe overlap. This can also happen with a very small frame. If your frame size is in the middle, you should not have any overlap. You would only notice overlap on sharp turns at low speeds.