As for a 1st time configure the RA through ASDM, as you get aquented gradually with the firewall I suggest to do a combination of both CLI and GUI, the GUI can teach you the way firewall pushes configuration by preview commands before they are send to the firewall.
AS for the RA tunnel my personal experience it is best to use a unique VPN Pool network to separate from any other inside networks or even the inside interface IP Scheme. As you create more RA tunnel groups in the future it is much easier to understand each tunnels by their ligical separation .
Here is a basic example of RA vpn config
http://www.cisco.com/en/US/products/ps6120/products_configuration_example09186a008060f25c.shtml
Rgds
Jorge
Jorge Rodriguez