Somehow I missed that he also looked at the negs with a loupe. TBH I am somewhat confused what to suggest here, because grain appearance matters when looking at the final product which in this case is a scan. "Mushy" only makes sense in a context of a given magnification. The image by @GregY above demonstrates this perfectly. There is not a hint of grain in a digital equivalent of a 2.5-inch print.
All films will begin showing monster grain eventually as you keep increasing magnification. But the thing about low resolution scanning is that it makes grain look ugly even on screen-sized JPEGs or tiny ink prints. That's why I suggested that his experiments with films and developers are premature, he needs to have an equipment capable of 35mm film scanning. V850 can't do it.
"That's why I suggested that his experiments with films and developers are premature, he needs to have an equipment capable of 35mm film scanning. V850 can't do it."
Thank You!