Quote: could someone be so kind as to also tell me, how many times would the bandwidth usage increase if I were to add a moving camera and update the client positions?
no one, i think. it's all reletad to YOUR implementatin of the project. my bet is to try a closed test run. run your game server app, make some automated clients (like bots) and populate them on your system. connect them via loopback for a first test and mesure system load for server process. this is the 'dirty' test, but even with this you can see how much memory eats your server app and after which number of clients it will crash the PC , additionaly you can sniff net activity (for packet sizes, for example) or drop diag info (like timeouts) from your clients into text files. with that diag info you can approximate your results for a bigger number of clients. do second test in simple lan (connect 2 PCs directly with 'crossed' cable /you can find info about this in the web/ if you don't have a lan) after you'll rewrite your server a little , you can make beta test with small team of friends over internet.
, additionaly you can sniff net activity (for packet sizes, for example) or drop diag info (like timeouts) from your clients into text files. with that diag info you can approximate your results for a bigger number of clients.