Tomorrow came and went and no drawing!
This is my take on what she said.
The blue circle is the big plate, the purple circle is inside that. The difference in the sizes should be the depth you want the collar. You said that you need it to be high up to cover your adam's apple. (yey me i don't have a visible one)
So that A is say 4 inches, the height of the collar.
That B thingy should be your throat measurement up there you want the collar to be. I'd suggest measuring over your adam's apple or it'll rub and not be the most comfortbale... let's say 15.5 inches.
You have to leave that bit below out... from the two green lines on the bottom. The outer edges need to be angled and open a bit. If not it won't pull together enough and it'll be too flat and just go straight out from your neck like a circle skirt when the girl is spinning around!!!
In drafting class one day, I needed to make a collar like this. I wasn't sure how to, so I took a piece of paper and made it into a cone, taped the overlap, trimmed it so it were flat around the bottom, like a dunce cap, and then drew another a few inches up and cut it again so I ended up with a round pyramid, sorta that was cut off part way up... so really it's a big paper ring... . Then I cut it straight up and it sprang open into a C-shape. did that makes sense or d oi need to make a video of that? LOL
Anyway, again to the collar...
You will need to play with the inside curve. It wouldn't really be too round, but you'll see that in the muslin. If the inner curve is more straight or curved, youll have a different angle on where the leaves your throat and meets your shoulders.