BIG-IP : virtual-server configuration for snat

When I create my SNAT Pool, should it consist of one or more Self IPs ? Is a SNAT Pool just a collection of Self IPs that BIG-IP dynamically selects and assigns as the request's origin IP ?

A SNAT pool should NOT consist of self-IPs. It should rather contain a list of IP addresses (not self-IPs) in the desired subnet. Further, the IPs in the SNAT pool are not actually dynamically selected. Generally, one IP is used until it reaches port exhaustion.