To answer my own question, I am trying to get to the point where I can make a graded Iodide core/shell emulsion. To do this, I need to hold the vAg constant while reducing Iodide from 100% to 0% leaving an emulsion that is 100% at the core and 0% at the surface (for all practical purposes) and which is about 10% overall Iodide.
To do this, I need to maintain a constant vAg or a known vAg for most of the make.
I also need to use up to 4 input jets with 3 of them salt.
This is going to be fun.