Multiserver architecture and other general questions

I'm hoping someone can point me to some documentation or tutorials of sorts, or perhaps answer the questions I have =)

I've got a Linode running BOA, as outlined in the install docs for getting that running, with 2 Octopus clients, but wanted to scale this out to fit a couple other servers, particularly a separate database server for dev and one for production, and perhaps extra web servers, again dev and production.

Seeing as how I just started all this on a single server, I'm not sure where to look/begin to scale this out.

In addition to this, how would I go about multiple users that need access to the same build/platform? For example, my coworker would need access to everything I'm working on with regards to my platform I'm creating. We've got one Octopus instance we would be working out of, and I have the credentials for that Octopus user, but I don't know where to go from here. My limited knowledge makes me think that there is one user per instance, though I'd like to grant another user the privilege of uploading/modifying the custom platforms that exist in that Octopus instance.

Any advice would be helpful, I'm trying to get our BOA/hosting environment set up at work with no real sysadmin knowledge.