I've been reading this thread with interest.
For me, pre-flashing *film* is not a viable option: it would mean re-rolling 120 - something I have never been able to do.
I *do* pre-flash paper - especially color paper. It is a "very" effective way to control and modify excessive contrast.
More and more, I'm gravitating toward "pure" negatives. I have softeners and all sorts of pre-lens filter, and the only ones I use are a few - very few - black and white; orange, green and, of course Red #25 (always with IR) and then on a very limited basis.
Where I do "soften" is in the enlarger. I have found in printing, that a "softener" over the enlarging lens can effectively reduce apparent "grain" (every once in a while I'll go through a Keystone Kops routine trying to use the grain focuser with a softening filter in place - there just isn't any "grain" to focus upon).
My favorite developer is Rodinal - and it is a "clean" developer - its action is not to increase grain size - but to present it with extreme efficiency. There is no 'smearing' of grain boundaries- the *big* secret of so-called "fine grain" developers. Everyone agrees to this: Excellent tonality - at the price of "baseball-sized" grain ... but ... I can make the "grain" go away with enlarger filtration.