The FaceGen Customizer is used to make a set of data that you can use to make a model compatible with FaceGen Modeler.

As I said earlier, the whole process took me about a month to figure out, and I even posted a tutorial that is on FaceGen's site. However, it's not for the squeamish, it's quite a tedious process. You have to morph the facial features of your model (say, V4) to fit the shape of their "mean face", and if it's off the morph and texture don't work quite right.

Just the calculations to transfer the model into a FaceGen compatible format take 10-20 hours, depending on the speed of your processor. What I usually did was set it up and let it run overnight. It takes about 8-10 hours on a Dual or quad core. If you don't get the face shape quite right, you only do PART of the setup process over again to tweak it. You don't have to go through the 8-10 hours of calculations again, it's more like 1 or 2.

Anyway, when you bring this "magic data stuff" into FaceGen Modeler, there are actually two underlying sets of data to work with, largely because of V4's overlapping UVs. There is one set of model data to use when you create the texture (because of all the different material uvs and how some of them overlap, so the geometry has to be broken apart accordingly to compensate for the overlapping UVs), and another set of model data to export the morph (which basically will be an UNTEXTURED head, neck, eyebrows, eyes, and teeth all welded together). 

After generating the texture and OBJ in FaceGen, I export the texture and the morph. I then take the welded OBJ (face, head, eyes, etc) into Poser and open the Group Editor. Then from that, I  spawn the individual morph targets, export each one out individually, and reimport onto V4 as morph targets. The result is a morph that CAN WORK with Mimic and the existing morph targets.

Now ... like I said earlier, making the models compatible with FaceGen isn't an easy process. I DO already have Michael 4 and Victoria 4 working in FaceGen. I COULD ask DAZ about distributing it, but I wouldn't be able to do that WITHOUT their blessing because the head geometry is copyrighted by them. A lot of people have contacted me after attempting to do the conversions themselves, and I wish there was an easier way to help right now! LOL

As for the workflow INSIDE FaceGen?  I should do a video one of these days. LOL But time has been precious lately. I'll see what I can do.

-- place 11 markers on the front view
-- refine 11 markers on closeup of front view
-- and for each side photo you pick (can have two) ... place and refine 9 markers

-- click a button and watch FaceGen calculate and morph the face while superimposing the texture. It's hypnotizing. LOL