If someone really wanted a forbidden colour like Coke Red for example (I do realize the original poster isn't actually looking for the Coke Red mix), wouldn't it be easily accomplished by simply taking a Coke can (or label or box) to a paint shop that has one of those colour match digital computer camera units? They "shoot" the can and up pops the correct mixture needed to get that colour. It may not give exactly the correct mixture Coke uses, but the end result will probably be identical (or as close to identical as possible) in appearance.
I think a combination of all the reds call it rage.0n second thought that may create a new **** storm.as to which colour to add first amount of each etc.