I'm sorry if my initial post suggested I was interested in disk space -- I should have made myself clearer.  The MB mentioned and question posted was referring to MB of RAM used and tuning suggestions for improving the performance of DNN.  I guess "instance" could refer to a number of things, but for purposes of this discussion I'm more interested in memory management, CPU utilization, and the possible configurations others have found useful in getting the best performance out of DNN.  Specifically what tuning parameters have others found useful in terms of optimizing SQL Server, IIS, and the other variable configuration parameters available on a Window Server to get the most out of DNN in a shared hosting environment.