Definitely there is some optimization to be done in the future to reduce the memory usage. 
Regarding preflashing I have a very good example from a Play Raw High contrasts in a man made wilderness, from @Popanz.
Print paper has limited latitude and predefined contrast, while film negatives can capture a very large dynamic range (easily 10+ stops). Preflashing is a simple hack of the printing process to retain some of the highlight details. Print paper is essentially flashed with some light before the negative projection, i.e. making it more gray-ish and taming down the highlights (have a look at this video for a real life example https://www.youtube.com/watch?v=lcx4ag7iygI). The price to pay is reduced contrast and saturation.
Using Fujifilm Pro 400h with +4 stops of exposure compensation, Fujifilm Crystal Archive TypeII with 0.15 print exposure.
On the top no preflashing while on the bottom 0.01 preflashing exposure through an unexposed film base (by default in the sim preflashing exposure is considered trough unexposed film). You can also tint preflashing by changing enlarger filters compared to the negative print exposure.