There should be some info in an Osprey book or two - if they aren't available in a nearby library, I've found that different Borders stores have different selections of Osprey books. They have a pretty decent WW2 section on the average, so even if they don't have any Osprey books that would help, you still might get lucky.
I have a few armor reference books at home (at work at the moment) and if I get a chance tonight I'll leaf through a couple to see if I have any pics that might help.
I found this link, but Websense at work won't allow me to access it
www.wargamer.com/Hosted/Panzer/panzer3b.html
so I don't know if it will help at all.