Hi Ray,
Thanks for trying NSUR. From what I understand, you want your user to sign in to each site separately at anytime they need access.
Unfortunately this is not the way a WordPress Network (multi-site) installation works. To get the experience you want you would need to have two separate WordPress installations and not use a WordPress Network (Multi-site). The reason is that with a WordPress Network (Multi-site) installation there is only one user table that covers the whole installation and Network(s). The user effectively logs into the WordPress Network installation (not the sub-site). So once logged in the Network knows who they are they get access to all the Network sites that they are registered with without needing to login a second, third …etc time.
What the NSUR plugin will do for you is allow the user in the first instance to register themselves with a sub-site on the Network (e.g. this doesn’t need to be the Networks main/primary site which would be the case without NSUR). After this, as I’ve mentioned, the Network will know the user. If they then navigate to a second sub-site where public registration is allowed they can register there or on accessing this sites admin (or private pages) they automatically get registered with the user list of the site. After a user belongs to 2 sites they only need to login to one to get access to both (remember there is only one user database table and they are not really logging into the sub-site but into the Network (Multi-site) installation.
So the simple answer is that a WordPress Network will not do what you want it to. I hope I’ve helped explain the reasons for you. Come back with any questions.