You may already have this document:
Vuescan has a raw mode but it isn't exactly raw in the meaning associated with digital cameras.
In raw mode the file contains only what the scanner recorded with no curves, WB, or any other parameters applied. But the image is rendered. After you save the Vuescan raw file, you can virtually rescan the raw data any number of times with different Vuescan parameters. The scanner is no loner involved. The advantage is: you only have to physically scan once. So, you can efficiently see how different scanning parameters, such as negative profiles affect the virtual scan. You can also work on the unaltered file in other programs such as LR, PS, etc.
There are many skilled Vuescan users here so I'm sure you will get more (and different) advice.