Install Process

I'm making plans to have my host set up a new account for a multisite install. I would like to use Pro Sites and Membership. I have watched the walk through for Pro Sites. I need to be able to give my host instructions about the install. I have read http://codex.wordpress.org/Before_You_Create_A_Network. Do you have recommendations as to the type of install (sub-domain or sub-directory, whether or not to allow end users to create new sites on demand) and instructions to give them prior to me getting it?