Steve, if you would like a few 325 gr WFN hard cast to include in your .444 test I'd be happy to send you a few. FWIW, I like drill mud for bullet testing. If you get the consistency right, you are left with a wound cavity that is measurable. After that, simple stir the goop up again, and fire your next shot. Unlike wet newsprint, drill mud doesn't wear out.
The 6.5 test was far more ambitious than any bullet testing I have attempted, but a few interesting trends appeared. Not the least of which is that bullets of specific designs and produce similar, if not equal results regardless of caliber. For example, your 6.5 X bullets behaved exactly the same as mine have in .243, .308, .375, .458, and .510, resulting in 1.5X expansion at the nose and a long shank. Thus from your findings, should an individual want to get a reasonable idea of the performance of a bullet type he has never tried before, your results would provide a good performance baseline, regardless of caliber.