Also you could probably reduce (but not eliminate) the distortion by putting in a non-slanted profile like the starting one at some middle point or something like 3/4 point along the sweep so that it would hold more of a regular cross-section through more of its length and only start to shift closer towards the end.

But I think you've missed the point which is to make something that looks like a miter joint at the sharp juncture in the sweep path.

- Michael