Solutions: split each cake in half, polish and etch to see if there's any pattern internally. Meanwhile, use the other halves as two contrasting steels (the first melt has more vanadium, plus I used bone charcoal in the flux, so it should have calcium, phosphorus, and other impurities while the latest attempt should have just iron and carbon.) Fold them together until I have the same number of layers as the existing material, then fold the two bars into the final jacket steel for the sword.
There has been some recent reserarch into the use of wootz and cast steel, imported from the West into Japan by the Dutch (the Japanese called it Namban steel) for making swords, so I'm still using what may be considered the appropriate materials.
Any flaws with my plan?