-.- Not gunna get into basic design concepts.
But The 'channels' are shared, and you can stick as much data in that packet as you want.
Every time you make a channel you have to worry about another mod using the same channel, if it does you conflict, think of things like block id conflicts. The less of the limited resource you use, the less you're gunna have an issue.
If you look at MC, it does the exact same thing. It tags it with what type of packet it is, the first byte, and then deals with it accordingly.
So ya, you only need one channel, if you can't figure out how to deal with only one channel, then you really need to rethink what you're doing.