Thanks killeroo. SSO was the first thing we figured out, at least for our environment, and that piece is already installed along with the Inventory/Web Client servers we're going to deploy in the architecture. It was a pain to figure out in the lab to the point where we're comfortable with it, but it's good now.
We worked with our DBA to clean up some of the performance statistics tables and shrink the databases, so now our largest database (of 4 vCenters) is 'merely' 25GB (was 57 before the clean up). Our larger databases MIGHT have grown as big as they did due to rollup jobs that handle performance related data not running correctly, so we're looking into the health of that as well, per the following 2 articles, so we'll see if we can't make things more healthy where all of that is concerned over the next couple days. Meanwhile, thanks for the vote of confidence regarding your 30GB database and upgrade time.