Hi Blue,
If you don't use a OneConnect profile and have multiple clients connect over the same TCP connection (through a proxy), you'd want to explicitly define a pool for both cases. There isn't any efficiency lost by specifying the pool in both cases. See this post for details:
http://devcentral.f5.com/Default.aspx?tabid=53&forumid=5&tpage=1&view=topic&postid=3392157229
Or you could add a OneConnect profile with a /32 mask and then not specify the pool in both cases. This would have the added benefit that server side connections would be re-used for the same client IP address.
Aaron