So, how do these "And" and "But" dice work?
Let's say your regular dice are red...your "And" dice are white, and your "But" dice are black.
A standard action test rolls one of each.
Using a skill, a piece of equipment or a situation to your advantage adds an extra red die (each).
Taking a risk adds an extra white die and an extra black (so you have a better chance of something awesome happening, but also a better chance of catastrophe)
Helping someone adds a red die (which contribute an extra success) and a white die
Hindering them adds a red die (which if successful might counter one of the active player's successes) and a black die
Since the game operates over a fixed timeline of 48 hours (this may be subject to change), and since a character can't cross their own timeline to correct one of their actions, then it makes sense that a player can take extra time to improve their chances...let's say that every die roll resolves an hour of action, if a player takes an extra hour to set up their action, they'll get an extra red die but this reduces their ability to possibly perform additional actions as the timeslots gradually fill up.
If either the black or white dice, match any of red dice, the player earns a number of points equal to the die result to spend on special effects.
Possible ideas are:
1 pt "and": Give a bonus red die to another character.
3 pts "and": Gain an extra degree of success (explain what has happened to cause this change of fate).
5 pts "and": Lock an event into the timestream.
1 pt "but": Suffer an extra "but" die on your next action.
3 pts "but": Lose a degree of success (explain what has happened to cause this change of fate).
5 pts "but": Suffer damage.
Still lots of thought to go on this...but the idea seems to have potential.