QueryCalc was designed to automatically generate efficiently executed reports and will guide you towards the creation of a well thought-out construction. Generally, just by the time it takes to execute. You may then examine the cells that are taking so much time. You can do no harm to the databases, to the HP3000, or generally do anything that is all that inefficient. Being aggressive is the only way you will learn.
Every good programmer knows the trick.
When you look at someone else's reports, think abstractly. The report you see won't be precisely the same one you need, but it is probably more similar than different. You already know a great deal of information about your own databases. Even if you don't know what the databases are called or where they are, you have a very good idea of what's in them and how important that information is to you. And you know what information you need to see.