Granted everyone has a different threshold for what's 'good enough' but long story short it's not possible to use a 30" ACD as a color accurate video monitor. FCP and Color are designed to just send proxy quality images onto the connect computer displays. The computer's GFX card is designed to send out a computer video signal and not a standard, broadcast video signal and the display itself was not manufactured to be a color accurate display for video.
Your only possible change is to buy the original Matrox MXO (not the MXO 2 or Mini but the original MXO) and give that a whirl but the 30" ACD isn't on the supported monitor list.
Lethal