Hi guys, got it to work using the UnwrapCurve plugin and after rebuilding the target curve :) Also actually building the flow object was now instantaneously. My mistake was not to Boolean Union the segments of the cable. History works beautifully now although with the many points on my rebuilt curve it is not very useful. In the future I'll just add some strategic points on the target curve to make it easier to handle. Anyway, it's now a fast and reliable workflow and means one less trip to polyland. Thanks everyone!