Since nobody said the clamp on bung was crap, I ordered one from GlowShift (free shipping saved me $7 so I got it on ebay). It mounted up just as I hoped and I just finished wiring the sensor in and went for a test ride.
While shopping on ebay, I fell peril to an impulse buy... I found master cylinder socks to fit my RCS19 M/Cs. So much for saving $7 on shipping, but I do think they look badass!