In my current game, which I unfortunately has been suspended because of work travel, had only 2 players. One player was new to the system and had one character, I also had 3 NPCs that I controlled. The other player rolled up a drafted doctor with no combat skills at all so he asked if he could control another character that would focus on fighting skills, i.e. he has 2 for a total of 6 in the team.
The guy with 2 characters does a pretty good job because when the combat starts he basically takes on the role of the combat character. his other medic character has good persuasion, leadership and other skills like that so he gets to be involved in a lot of the out of combat scenes with this character. The other player with one character has a very combat oriented character but is also the only one who speaks any Polish, so he is involved in most role-playing dialogue scenes too. The whole situation works quite well.
Having said that, I'd rule against it if you have enough people at your table. 4 is plenty so I strongly suggest letting the additional players be NPCs.
here are a few things you might also find useful:
a map of the are in a pdf (if you have pro you can edit it). I use it to keep track of what's where and where I can get info (which sourcebook) for a region.
http://sites.google.com/site/leonpoi...edirects=0&d=1
Encounter tables in Excel. it's for 2.2 but it shouldn't be much different. No instructions but it also has a macro for motivations and a few other things.
http://sites.google.com/site/leonpoi...edirects=0&d=1