(just preparing to configure my first Slony setup and reading docs,
 which seem to contain different opinions)

There is machine MST on which master database runs.
There is machine CLI on which subscriber database is to run, from
which slonik scripts are to be executed just as most psql-s.

CLI is able to reach MST 

MST is *not* able to reach CLI (bah, it even can't address it at the
moment)

Will Slony-I work in such config, or not? 
After reading http://slony.info/documentation/plainpaths.html
I feel that it should, but a few other articles tend to require
any-to-any communication paths.

So - do master need a connection to subscriber?

And if so - for what?
(I understand that it would be needed if master had to read events
 from subscriber, also if I were to swap master with backup, but
 is this all?)