Fuck. I just submitted mine today and didn't see that last part. I put dither on the master fader and mixed it down to 16bit 44.1kHz wav files.
I don't remember if I fallowed your -6 and -13 rms levels or not, I just set the levels where I thought they would go well together and let them be.
I just downloaded them. No worries, I can fix the .wav and rms. Not sure what dither does...