Nah, I'll let you figure it out by trial and error.
Ok find, here are some of my suggestions:
If your overflow siphon breaks and it stops draining water from your tank. Now your return pump is going to empty the return section of your sump into your tank. So make sure your water level in the tank, and the size of your return section, are matched so that the tank can "absorb" the water from the return section of the sump, and you won't flood. You will burn out your pump though.
If you want to avoid burning out your pump, install a float switch to detect a low water volume, and cut power to the pump if the water volume is too low.
Are you using a CPR style overflow box, or a u-tube design? Make sure each end of the u-tube (if you are using that style) remains submerged in water in the event of a power failure, and restarts when power comes back on. This is easy to simulate.