Jim is a great guy... I love to stop in his shop & see what he's got. Over the last couple years I've seen an original Spencer carbine, several Parker Hales and many other pieces of interest to me...
As to Brogans nails were most common. The heel plate is up to you, they were a catch as catch can item not an issue piece. THey were apparently quite favored as they provided some traction on wet groud but they were no help in winter conditions. My own experiance is that they are quite useful... though on concrete even w/ the heel plates I feel like a hog on ice.
These are two vendors I've had good luck w/ in the past. The second provided my brogans and I am quite happy w/ them. They are sewn (which was done in some of the mass produced variety) instead of pegged so most modern shoe repair places can easily repair them which is a plus.
www.missouribootandshoe.com www.umvmco.com
Good Luck