I have one or two ideas. I haven't exhaustively read all you're written so you may have already covered this. My apologies if that's the case.
1) Poor man's quenching oils and speeds. How fast is ATF compared to, say, canola oil? Are there benefits to mixing different ones at all? For those of us who can't afford/justify buying legitimate quenching oils, what are some fast, medium, and slower quenchants that you can buy at Walmart? : )
2) This is maybe a little basic, but, when it comes to oil quenching steels, which ones work best with fast, medium, or slow quenches? I'm thinking 1075, 1080, 1080+, 1084, 1095, 5160, 9260, the W series, 52100... Those are just the ones that come to mind. Not exhaustive (thought that seems like it could a pretty big undertaking).
There's my two bits (and it's probably not even worth that much).