For the Simplex Competition front changer (derailleur), the 1952 Simplex catalogue (available from Chuck Schmidt's Velo Retro) says "Grande capacite d'emploi (52 a 28 dents)" and it also says "Convient pour la course et le cyclotourisme." There isn't another distinct model, excepting the chainguard attached variation). A 1957 Simplex parts catalogue shows only one model of Simplex front changer (excepting that chainguard variation). So I was mistaken about two cage depth models being available because I don't see them in these catalogs, perhaps confusing the earlier Simplex lever changer (which has a different cage design and lever mechanism) as being concurrently available.
If you wish, measure your cage when you get it, and email me offline and we can compare.
Peter ...................................... Peter Brueggeman La Jolla California USA pbrueggeman(AT)ucsd.edu
"...That does look like a fairly deep cage.... The one I'm getting looks shorter...." John Betmanis