I tend to not document well, but this is an INTENTIONAL project.
There may be overkill on documentation.
Plus a dozen others that were largely irrelevant, and conversations with experienced dyers
Did you read each of those? I did. My memory is like a colander, though, and I don't want to leave a detail unattributed.
There are similarities and discrepancies. Some discrepancies are made clear in some places but not others. Some discrepancies are due to intended goals - a tye-dyer or someone who is fine with the fabric fading over time will have a different process than someone who is trying to dye a rich, solid color. Some discrepancies are due to mordant preference - someone dyeing for modern purposes may prefer a different mordant. Each source is weighted by intended outcome, and I will use an amalgam of the most appropriate sources and most frequent advice.
One discrepancy is the scouring process. Some have aggressive scouring methods with almost-boiling for at least half an hour with special scouring soaps, some basically say to wash it in cool water first. This is because of discrepancies between FABRICS. Only one source specified - a pure white silk with a soft hand has already been de-gummed. My silk source specializes in fabrics for dyeing, and it was already pretty close to ready - a simple lukewarm handwash in scouring detergent followed by a wash in gentle shampoo left me with a nice hand (I would have left it at the post-scour, but I am still waiting on mordant and dye.)
Another discrepancy is in the use of hide glue. The hide glue is to protect the silk proteins from the indigo. Given my nervousness about using silk at all, and the fact that I have hide glue on hand, I will err on the side of caution and use the hide glue. I want this garment to last a long time, and I am not gentle on clothing.
I knew there were some considerations regarding metal to consider (something loud and shrill in the back of my mind insisted that Steel is Bad for Natural Dye), but the sources didn't specify anything, so I went to a trusted source who I know will patiently answer my stupid questions. Boyarynia Ceara of Novogrod advised against using a stainless steel pot, as any iron it may leech is a saddening agent. She advised me to use the biggest, cheapest aluminum pot I could find.
Most sources advise starting the indigo mother in a separate container. Most just said "wide mouth jar" with no size. Ceara confirmed a quart jar was good.
The indigo supplier advised alum and thiox for the mordanting process - I will trust the person who makes the dye to know what their particular formula will react best to.
Some sources say to dip the fabric for roughly 30-60 seconds, then oxidize, and dip again for 1-5 minutes each subsequent. Others say to soak for half an hour. However, the longer dips allow more indigo to collect on the fabric, it fades faster - fewer indigo molecules are in contact with the fabric molecules as they oxidize, allowing the dye to wipe off the surface. I am going for long-lasting dye, so I will do more, shorter dips.