missing domain mapping instructions

I am just about to lose a client because his site is down. Either problems with his registrar, incorrect settings on my end or both.

Can someone explain these settings and then later at that to the usage guide as its missing. (See attachment.)

The issue is that I never add the www version of the domain name and get a valid health mark. If I add the non-www version I get a valid health mark, but that doesn't help me as the client wants www AND that's how its indexed in Google.

So questions...

* what is the proper setting in the drop down?
* should I just have an A record pointing to the IP with the registrar and then a CNAME record for WWW? (Currently the client has an A record for WWW and * for wildcard.)

Desperate for clarity.