I’m sharing my rather cryptic notes here, without explanation or illustrations since I need it save it somewhere before I forget …… Will add explanations later. 
Install Donncha’s Domain Mapping Plugin
Register domain name for the individual blog
1. Get IP Address. Start -> Run -> cmd -> ping http://main mu site
2. At GoDaddy, go to domain manager for main mu site and copy down nameserver info
3. At GoDaddy, go to domain manager for individual blog name
Change nameservers to to the names copied from main mu site (Select custom nameservers)
AND under Total DNS Control and MX Records, change the A (Host) record = @ Points to IP address of main mu site
4. At the main mu site, go to the individual blog. Click Manage -> Domain Mapping
Enter IP address for main mu site
Enter the registered domain name for the individual blog
5. Wait for new domain address to resolve
