Many people do not like the custom stair tool and it has been removed from the default Vectorworks workspace. In order to find it you will need to customise your workspace, locate the custom stair in the legacy category and add it to your own workspace. The Custom Stair works differently than the main Vectorworks stair tool in that it works on the concept of parts. You add a flight, then you add a landing, the new and another flight, then you can add another landing or winder, then you can add another flight, and so on. That makes the stair extremely flexible, much more flexible than the standard stair tool.
Solar studies seem to be getting more popular with building professionals and building authorities. I am hearing a lot of my clients are being asked to provide a solar study showing the effect of their building on the surrounding properties. Of course the other reason to use a solar study is to see the effect of those surrounding buildings on your project.