Do I need to modify default NAT setting when setting up Dual WAN

[thenewguy1979]

On the Pfsene guide below no change in NAT setting is required for dual WAN:

http://doc.pfsense.org/index.php/MultiWanVersion1.2

However on this guide below it's need to change to AON instead of automatic:

http://katsudon.ipos-asia.com/?p=6

Question is can I just left NAT outbound to be automatic or do I need to change it to AON like in the second link.

[ktims]

You don't need to change it. Just the default firewall rules need to change.

[rudraansh]

Whenever you use a MultiWAN Setup You create a New Gateway IN Load Balacing Services.
So all the request from the client side has to go through that new Gateway.
You will set in Firewall Menu–> Rules--> LAN Tab