I used FreeRam function to test how much RAM is being used.
Running my clock sketch it shows from 1167 to 922 available (depending which menu I'm in).
However as soon as I enable Waveutil.h library it jumps down to 110 bytes. I'm not even playing audio at this point. So I don't think there's anything I can do to optimize it (I don't want to mess with WaveHC library) other than upgrade RAM