Few questions regarding Domain Mapping

First, I just want to say, I run a multisite just recently signed up to pay 79.00 for WPMU dev premium, and for the amount of stuff I get, it is my favorite expense to pay :slight_smile: Finding you guys was literally a godsend..

Secondly (hehe), just had 2 questions regarding domain mapping. I'm using a plugin (dsIDXpress) that only works on one domain name. Because of that, after I've mapped a domain, I have to go to sites --> edit (for the site in question) -> settings tab --> and change the 'home' value to http://mappeddomainname.com (instead of the subdomain that's normally in there). This makes it so that when in my dashboard, I see 'mappeddomainname.com/wp-admin/ instead of subdomain.agentfire.com/wp-admin/

Question 1)
Once I do this, whenever I try to go to the sites dashboard, it makes me login again. Is there any way around that?

Question 2)
While in there, I noticed under the info tab, there is a 'domain' option, and a checkbox that says 'update siteurl and home as well'. Should I change these to http://mappeddomainname.com from the subdomain value? I'm concerned about SEO and want to make sure I'm doing everything by the books. Also not sure what to do with that checkbox.

thanks!