As long as your system is properly primed then how "Tight" your automation is wouldn't matter. When I used cooling reactor set ups I always felt safer being able to run at least a quarter cycle without any cooling.
I don't understand what you are trying to say here.
If you don't have a tight automation, then you might get enough extra heat to blow up your reactor. It doesn't really matter how many iterations it has to go through, when you're talking several thousand heat per second, it only takes one tic to turn your reactor into a crater.
I was thinking about something like this setup with MOX fuel. You can get that bad boy up to around 18k heat before anything bad happens. So you're going to be looking at INT((18,000/22,100)*4 + 1) = 4, which is the maximum multiplier possible. In fact, you could drop it down to 17,000 heat, still have the maximum multiplier, and have 1k heat as a buffer before anything bad happens.
In such a setup, it would be producing 1600 EU/t, but would have a micro-cycle time of only around 160 seconds (assuming heat is also quadrupled).