Knifegrinder is right, usually if you encode a mono wav file it will come out half as big as a stereo file anyway, even if the output file is stereo, because the sound data on both channels is the same. So downmixing to mono before importing to C2 should work fine.
how? 96 kbps is still 96kbps, mono file is not shorter in half. so mono file is same size, just twice as good in quality. hence 96kbps stereo is actually 48kbps per channel, mono is 96 kbps per channel, but still 8 second file encoded with 96kbps quality should weigh 96KB despite being mono right?