maybe an output multiplier. Like 2 for double output for same ingredients or 0.8 for 20% less etc...
Can't output 0.8 of an item, of course, so that would need some kind of output buffer system to be accurate, which is more effort than I'm willing to put out.
The only simple way I see to do this would be the modify the output count of all the item recipes in the game. That would include any building that the player crafts by hand.
For decimal values, I would have to just round up any decimal to the nearest integer.
For example, with a output multiplier of 0.5:
- A vanilla output of 1 would still give 1.
- A vanilla output of 2 would give 1.
- A vanilla output of 25 would give 13.
Would you want this?
But for the crafting/mining speed stuff - sure, I can make that.