I can't speak from any sort of experience but I did find a helpful .pdf on "Transformer Winding Design". It doesn't seem to directly answer your question, but it definitely taught me a few things.
"Rectangular core and coils and layer windings offer the advantage of lower costs for manufacturing compared to power class circular core and coils with disc and helical windings."
__________________
The early bird may get the worm, but the second mouse get's the cheese.