I only play on Nutaku not DMM is there a simplified/complete explanation of RCs somewhere? Do all gold give same/similar RCs? likewise for platinum and black. I understand all event units give low amounts but is it always the same # or does it vary? Or do all units (gold+)give a wide range of RCs?

I assume unit lvl, cc, etc are meaningless.

What about the units u buy with them. Are they unique or are they in premium summon? How many are there and how much do they cost?

Thank you for any answers and sorry if what I'm asking is not easily answered.