So the way that Flow might help with curve construction would be to first draw a 2D curve in the Front view that has a rise and fall to it, and have a line underneath it kind of like a shadow:



Then you can draw in a separate path curve in the Top view so you've got 3 curves like this:



With this kind of arrangement you can then select the "rise and fall" curve, then run the Transform > Deform > Flow command, and then pick that shadow line underneath it as the base curve and select the other one as the target curve, and that will produce this kind of result:



So you can kind of get an idea there that if you're able to kind of deconstruct the result you want into initially straight components you can then use Flow to deform them onto a new path, so you can kind of build things up by adding one element of shaping at a time which can be easier than trying to directly model the final path all in 3D.

Similarly you would focus on making a weave that was on a plane and then map from the plane to a cylinder shape.

- Michael