Regarding normal clean up altitude
FWIW. Clean up altitude is based upon two primary considerations, safety and noise abatement and secondarily, economy. 800 to 1000 foot clean up altitudes have been traditionally, the selected safety compromise. The best configuration for an aircraft with a failed engine, airborne, is clean. So, we want to get to clean as soon as it is safely possible. Noise abatement considerations can raise the cleanup altitude and because we are gaining altitude instead of speed, it is not much of a safety concession. Instrument departure procedures may also influence configuration because turn radius, at a max 30 degree bank angle, is a function of speed. So, slower leading edge out turn, is a tighter turn.
all that said, in an emergency, especially day, vmc, no obstacles, you do what you have to do. Cleanup may be 500 to 600 feet agl.
sorry for the pedantry but there are clearly many here who do not understand these matters.