As there still seems to be a lot of misunderstanding regarding this format. Let me try to explain it clearly, as I understand it.
You can only use cards that are in the chosen colors for that match.
However,
You may use any mark.
You may use any pillars, including quantum.
You may use "off" color quanta to activate card abilities.
A card that is in an element, yet has no casting cost (say nova), may only be used if it's element is a chosen element for that match.
You may change decks, and marks between rounds of a match, but are not required to.
Your deck may be mono, duo, trio, rainbow, or any combination of the "allowed" card elements for that match.
"Other" mana cards, like Hammers and Daggers, are permitted.
If this is incorrect in any way, I encourage an organizer to me straight. Otherwise I think I have covered the common questions, and I hope it makes things more clear.