If you double click on the Output Fader, the level will be set to 0dB.
But what with FXs that could increase the peaks of the original recording?
So far the only way I have found, is to add a limiter at the end of the Master FX chain, where Sonics’ are useless. I have found Ultrafunk FX Compressor and db Audioware Master limiters the best to handle this type of overloading in CDA.
So Sonic - you really should come up with a solution to this, and a lookahead limiter included in the Master mixer would be fine for me.