Useful description of Carmina lasts by Ethan over at The Armoury thread.
The Carmina lasts are all width specific - from my experience, you cannot get a narrow last made wide, nor a wide last made narrow. Rather they have lasts that are narrow or wide, with different shapes and toe boxes per last. What we currently carry are the following;
Simpson - a narrow last with a chisel toe. Reasonably extended in the toe box, and a reasonably narrow waist. E width.