I would suggest having multiple origin servers for your setup. 200 incoming 1Mbps streams is probably too many for a single server. Also, for tuning, I would try the following GC settings as suggested in the tuning guide:
Latest version of Java 7 seems to perform best.
-XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:NewSize=512m
Also, take a look at the suggestions here for increasing the incoming UDP receiver buffer size:
As far as hardware, we suggest the most recent SandyBridge processors.
Another technique that people are using is to run more than one instance of Wowza Server on the same machine. There seem to be some peformance limits to running a single instance on a server. To this you can duplicate the WowzaMediaServer folder and edit bin/setenv.sh to point the following variables to the second location:
Also, edit conf/VHost.xml and conf/Server.xml and either make sure the two instances bind to different IP addresses (dual home the machine) or use different ports for each instance. It is probably best to dual home the machine.
Also, be sure you are licensed properly. If using monthly or daily licensing than you are all set. You will be billed properly. For perpetual license you will need to purchase a license for each instance.
I hope this helps.