I’ve only digitised negatives with a DSLR or an Imacon scanner (have only used VueScan to scan positives) so I can’t say anything very useful. This thread may help until someone more knowledgeable comes along.
https://forums.negativelabpro.com/t/understanding-the-lock-exposure-setting-in-vuescan/4246
The main thing in most negative scanning is to set the exposure so the histogram shows the film base near the right edge but with no clipping.