The 20 slot limit being mentioned is just in regards to the demo connecting to freenode. The demo connects to freenode from a single IP address and freenode has

The 20 slot limit being mentioned is just in regards to the demo connecting to freenode. The demo connects to freenode from a single IP address and freenode has limits on how many connections you can have from one IP. It's not something you need to worry about in a normal use-case.