Hmm are you sure that is the right stuff? Maybe it doesn't matter but the stuff originally put into our MBs is in a white bottle and is perfectly clear in color. The lubricity properties of it is very nice but unfortunately any slight leaks make a white gunk that looks like corrosion on a battery.
Well the directions on the flush I used (Zerex?) said to drive 300-500 miles and to be certain not to have antifreeze in with it. So I drained it and completely flushed it once, then filled it and ran the flush fluid into it. For me it turned out to be about a week's worth of driving, so I was just really careful keeping the temperature below 90*C. If I recall correctly I had a thermostat that was stuck open back then so it wasn't much of a problem. Cavitation is a long term problem caused by both the boiling and the difference in temperatures, so in the sense of different temperatures water would be better against it but for boiling it isn't. However if the temperature went a little over 100*C in the system hoses and other components will blow as the water will be boiling a little over.
Before doing the flush I seen rust and crap in the head, almost made me feel sick, weeks later I looked again and the insidie of the head was as clean as a whistle (the stuff that came out with the flush looked BAD).
