Digital BW, The Print

First,  even stains in negatives usually prove inadequately removed
antihalation dye...insufficient fix/wash. It's equivalent to fog when
printing or scanning..it reduces contrast evenly but may suggest the
negative wasn't adequately fixed/washed.

Second, very few people use staining developers, probably nobody with
 TriX/Holga. Staining developer ideas simply confuse things here. 

COMPLETELY OFF TOPIC>>>It happens that I've inquired of folks who DO
use staining developers and scan...they've told me scanners treat the
stain identically to silver..it's considered colorless density by the
scanner when in B&W mode, just as it is when using an
enlarger...that's the whole point of a staining developer! (some say
the stain color is faintly noticed by polycontrast paper but not
significantly.

Just to make the point about file size, a B&W neg that I just scanned
as as if it was a chrome is 120.3MB...(can be inverted in Photoshop to
look like a positive...not necessary with Vuescan, best practice with
Nikonscan). The same neg scanned as a B&W neg produces 40.1MB and
won't have to be inverted. 

John