The 1:1 page is for the inbound connection.
It can get crossed up if you do that manually, so traffic comes in one IP and the reply is sent out another. That generally doesn't work since the other end drops the reply packets.
I'm pretty sure pfSense will just automatically do it right. If you can connect out from the servers using 1:1 then connect out to whatismyip.org or something and you can see what IP you're connecting out on.
On the outbound page what I was trying to say was that any rules entered there are processed in order, like firewall rules.