Find the maximum peak level of the music in your editing software, and use that to set the threshold of your limiter just at/slightly above/slightly below the music's maximum peak level. So, if the music alone peaks at -6dBFS and the clapping drives the peaks up to/close to -0dBFS, you can set the limiter threshold at -6dB(FS) and bring up the rms peak levels via make-up gain.
I am not specifically familiar with the WAVES plug-ins (I think the L1/L2/L3 Ultramaximizer plug-ins combine rms normalization/compression with limiting - someone please correct me here), but a limiter essentially allows for setting a 'threshold' or maximum level to which audio peaks may reach. A 'hard limiter' will suppress all peaks, no matter how transient, at the threshold you set; a 'soft-knee limiter,' on the other hand, will allow more transient peaks to pass the threshold while effectively suppressing non-transient peaks that would otherwise rise above it.