Hey!
I would say that the written exercises don't tend to be too dissimilar from the written exercises that you would get at AC stage. In my experience, they are usually still quite commercially focused - for example, something such as acting for a PE firm and putting together a short report on which company to invest in from a range of options, based on the information you have been given. Usually, the way that you do well is by explaining your thought process and backing up the points that you make with the evidence provided - there isn't usually a right or wrong answer!
The main difference I found was the timing, and my VS written tasks were often slightly longer than AC ones - most of my AC exercises were around 30-45 minutes, whereas on a VS they were more like 1 to 1.5 hours. That extra time usually means that you are expected to go into slightly more depth or structure your answer a bit more clearly, rather than being a quick fire task under pressure.
Overall, if you are comfortable with AC-style written tasks, I'd say you'll be in a really good position going into the VS! Best of luck!!
