I needed a 72mm spacer for my xh a1 in order to attach the Brevis. But I have the pre-flipped version, you don't need the spacer with the flipped Brevis.
That's correct. The flip, or non-flip are a direct fit for the DVX, and if you move to a different HD camera later, all you'll need is a step-up or step-down ring depending on it's threads.
Keith, you'll find pretty much every question answered over at our Video University. Start with the overview video. The whole video university concept was put into place so everyone from novice to expert would find something useful.