I'd appreciate a little input on how to properly utilize DA (and possibly multi-site) in the following scenario:

I have a site at www.mysite.com. The business associated with this site (in part) hosts and manages websites for multiple companies within the same industry. The content on www.mysite.com will be completely separate from the content of any other sites. It's the front-end marketing site for the business.

The companies for which this business will be hosting and managing websites will use a combination of separate domain names (www.othercompany.com) as well as subdomains of the main site (companya.mysite.com) depending upon which features they select. Each of these sites can have distinct content, but will also share content as well as utilize some of the same blocks, themes, views, etc.

In my mind, what makes sense is that I do a D7 install on www.mysite.com and treat it like a standalone site (which it is). And then I use a multi-site install using a subdomain like clients.mysite.com. And then in clients.mysite.com I install DA to manage all of the client sites.

I do have complete access to my server using cpanel although I've never setup a multi-site with a subdomain, only separate domains. But I assume it's doable.

Doing it this way, I'm keeping the front-end marketing site (www.mysite.com) separate from the others since it's content is unique. But I'm sharing the D7 code base so I'm only dealing with one D7 installation to update and maintain. And then using the clients.mysite.com as the DA domain, I'm able to utilize all the benefits of the DA module to share content and other features between the client sites.

Does this make sense? Is there a better way of handling this setup?

Thanks