I have to say, tho, I've never used Rodinal that strong and don't know if dilution is a factor. The tonality matches but the detail isn't there. SPF-3 looks good to me.
Given the unusual solubility (amount and curve) my idea was to fractionally crystalise out the tetra and leave any more soluble contaminants in the supernatant. I didn't do it in the end. I merely weighed the plastic pots and contents, making a note under them and will reweigh when I need to open another one up for use. This assumes the contents were indeed tetra as stated on the MSDS to start with.