I can't find any CR documentation that lends credence to how to handle what happens when a spell asks about what colors of mana were paid as part of a spell's cost, so I would appreciate any CR documentation that can be provided for personal reference.
I control
Mycosynth Lattice and am about ready to cast
Boros Fury-Shield.
If I pay for the Shield using {2}{W}, spending one of the colorless mana as though it were a red mana, do I get the added effect?
Contrast this with: If I pay for the Shield using {2}{R}, spending the red mana as though it were white, do I get the added effect now?