Go for time rather than number of iterations
Usually with fuzzing I want to fuzz for a certain amount of time rather than until a certain number of tests have been performed. Eg. “I have these machines for X hours, so I want to do as much fuzzing as possible but be sure my fuzzing is finished and I copy out the data within that time frame.” Or, “I'm going to go to lunch for an hour and I want to leave the machines fuzzing and fix all the fuzzer bugs I find when I get back.” I don't have a good sense for how long it will take to fuzz X number of tests, and it varies if you're running on different machines.
Again, this is an issue we discussed in a meeting but I want to put it in the issue tracker so it doesn't fall off your to-do list.