I'm setting up cpanel on a new ISP account so I have some basic questions.

1. When I got to the resolver setup, it said it was set to local resolvers only during setup
and said something about changing it back or something like that after the setup is complete. What are they talking about, and what if anything am I supposed to change back. The default for the nameservers was in the second and tertiary leaving the primar blank. Should I leave it like that or put the two nameservers in the primary and secondary?

2. I have several IPs. My root has a shared IP that looks like I am not supposed to
put a domain in. I am setting up some domains to have their own IP and some as addon domains. The question is about the ability to access files in my root using a cgi perl path
like "/home/domain1/public_html/file.data. I would expect it to work for at least in in an individual account and its addon domains, but should I also expect to able to use this type of path to read a file under my root in a different IP and account. Is there any way to set it up or give permissions so I can do that?

3. I checked the box in server config>>Tweak settings>> allow nameserver IP sharing.
does that have anything to do with what I am trying to do above.
What does this do? When do I need it checked?

Thanks