Matt made a good point that it sounded awful complicated and that he wanted something more "out-of-the-box". So, I went back to the drawing board. The only reason to add a helmet to the head of a pawn is because you want more bulk or you want to change the shape slightly. I was willing to sacrifice accuracy for simplicity  as long as it saved time.
I decided to try my hand at a Corinthian helmet. Basically there are a few key items that define it:
- The line coming to a point on the forehead, running around the helmet, essentially dividing the helmet into two pieces: the 'bowl' at the crown, and the guards at the cheeks, nose, and back of the neck.
- The guard at the back of the neck typically had a flair where the metal was rolled.
Start by making a '+' with a drafting pen (using permanent ink) on the top of the pawn's head. This will become critical in making the left and right symmetrical. Carry the lines down to the bottom of the head.
Draw the point on the forehead and slope it down and to the back. The slope should be just over the ears. Rough out a shape for the face by defining the nose guard. Add the cheek guards. Finally, rough out the shape for the ears and the neck guard.
Now dab some Gorilla Glue Super Glue to the point on the forehead and affix some thin packaging string. For figures smaller than 40mm you may need to use thread. Using Elmers School Glue Gel run a bead along the lines you've drawn. Using a small amount of Super Glue, you can set the Elmers quickly. Don't worry about the mess; we'll deal with that later.
Do the same with the neck guard. It only goes from the back of one ear to the back of the other. Make sure you harden the ends with super glue as we will need a firm surface when we trim it with an X-Acto blade later, so soak the string in super glue.
Use a piece of scrap craft stick to make the comb (the holder for the horsehair crest). My larger sanding drum for the Dremel fits the shape of the head near perfectly. Using the line you drew earlier, make sure you align the comb fore-and-aft.
Yes, I know at this point he looks like someone who has a board for a Mohawk or Steve Martin trying a new gag. You might be tempted to just use the craft stick for the whole comb and crest and let the paintbrush separate the two. I wanted to experiment a little more, so I decided to use the sander and trim this down to a comb. I started by cutting it down with wire snips, then using the sander.
I used glue gel set by super glue to fill in any cracks or gaps between the comb and the head. After it all dries, go back over with an X-Acto knife with a fresh, sharp blade and bevel the ends of the string and cut away any excess blobs of glue.
Now for the painting. We roughed out the shape using a pen, but will use a black undercoat to define the actual edges, so here is where you can correct your mistakes, if any.
I usually use Google Images to find ideas. Here is a search for Corinthian helmets so you can get an idea of shapes. The eyes should be pointy-er and the cheek guards point down past the chin. Oh well, maybe on the next one.
Here is a picture of what it looks like painted, before I put on the crest.
As you can see from the side view, it is a real Cartman-style face. I'll try and fix that next time with a more three-dimensional nose guard. We'll also see what happens when I try to make a horse crest out of yarn. Finally, I may decide to do something about adding a third dimension to the cheek guards.
 Making a unit of 20 French all at once has made me appreciate cutting down as many steps as possible. It is fine to hand-craft parts for a figure when you are making figures for a skirmish game (i.e. 20 figures per side, at most), but when 24 figures forms the basis for one unit on a side and you need eight or so, it changes your approach.