thanks for the help. I'm basing them individually, and I plan to play them mostly after 1942.
I've got enough figures for 3 10men squads, with this organization :
NCO with SMG
junior NCO with rifle (edit : in fact, just normal riflemen, I don't think there is a specific junior nco figure in my set)
6 riflemen...with rifle
LMG with 2 servants
Plus an half dozen riflemen with "german" typical grenades, an officer with SMG (and his assistant with rifle), and a 2men "small" mortar team, and an extra smg guy.
I'd like to build a "credible" rifle platoon, if a few extra figures are needed, so be it

edit : problem solved, apparently I have everything needed, and assistant squad leaders with rifles are not a problem. I'm still searching for infos on grenades figures, but maybe eveyr german trooper can carry hand grenades, and the ones I have are just some nice new poses to add some variety in the squads, nothing related to organisation.