Choice of "WCF Binding
" is based on "Transport Protocol
" which you want to use for communication
between your WCF Service and Client Application.
This link has in depth information on "WCF Bindings
Your concern/intention seems to be with Availability of your Service for multiple incoming requests. WCF provides a very good feature for this, and it is - "WCF Throttling
This is one of the very good Article on "WCF Throttling