Y'all got me so curious I couldn't wait so I decided to DC today. I DC on dry when I use GPB so I poured out what I estimated to be one ounce (judging from the contents of a jar that has 1 ounce when new). Just as a further check, I got a calibrated cup and poured in 4 oz of water:
This is how my hair looks after I've applied GPB relaxer style to dampen my hair and coat it thoroughly. I didn't even need all that I poured out:
I usually apply enough till my hair feels damp and it seems an ounce or so is all I need for my whole head. Because I'm in twists, I find I have to use a bit more so I can squeeze it into the twists. If my hair were loose, I'd be able to apply to sections that were a few hairs thick and so could probably be more economical due to being more efficient. Still one ounce seems sufficient for DCing on dry. I imagine when my hair is wet, I probably use less. Of course when my hair is longer, I'll probably need more. I used what was left over on my ends rather than throw it away but it felt so wasteful coz it was more than was needed. I didn't want to put it back in the bottle coz it's no longer "fresh".
ETA: I do have fine strands so I guess that does make a difference.
I decided to add a photo of what my hair looks like once shampooed and then conditioned regular and ACV rinsed then left to drip dry, which is basically what I do after a GPB DC, so you can see what it looks like w/o product on it:
E(again)TA: Below is a photo of the bases of the cups I was using to help me estimate the amount of GPB I use to dry DC. The one on the left is the one that had GPB and the one on the right is the one that had the 4 oz of water. That would explain why the height of the 4 oz of water wasn't that much greater than that of the GPB: the water was spread out more.