It was hard to get good measurements on some of these dimensions due to how closed up my cabinet is, but I tried to collect a good set of numbers on the 990's footprint. As best as I can tell, the back edges of the feet are 0.5" to 0.75" in from the rear edge, but they're close to 2" wide so you could probably have the better part of an inch of rear overhang without getting into trouble. Below is a summary of my measurements from this morning (keeping in mind that I didn't measure the depth of the jacks themselves, cable connector and turning radius clearances are not addressed at all, and I took all these measurements with a 25' tape poked into a closed cabinet):