What I'd used with that unknown powder stuff was 3 or 4 grams in the 9 oz of olive oil, if I remember correctly.
Grams + ounces??? Joking....kinda LOL 9 x roughly 28g = 252g
I don't have a preference for either, but calculating the 2 as they are....not gonna work
So, approximately 252g base oil.
If me, I would use at least a 5% usage rate for the plant colorant - dependent on the colorant of course. Some may need a little more, while with others - like indigo - you may find that half that amount is sufficient.
5% of 252 is 12.6 grams. I'd round it up to 13g for the 252 grams of base oil.
I haven't really decided yet though what to actually use. I've mostly been researching other people's experience with alkanet when soaping, and basing my plans off of that info. Only thing there though is that most information I've found is about using alkanet in cold process, or in cpop, but I've been making my soaps as hot process.. Does alkanet behave the same with both cold process and hot?
I have not yet delved into hot process, although I will at some point, so I can't say with 100% certainty.
Buuuutttt.....based on my logical deduction, which itself is based on my experience with alkanet gelling in cold process soap, I would have to assume that this colorant would behave similarly in both as both cp & hp can heat up significantly, whether through the 'cook' or through gelling over several hours.
Then again, I could be completely & totally wrong And that's one of the reasons I love playing!
Good luck on your alkanet journey