1) when staying in the circuit climb to within 300' of circuit height before turning xwind
Remember these are only "recomended."
Its going to depend alot on the aircraft that your are flying. Some of the guys i follow around bashing the CCT fly wide eough as it is and they all turn at 500' AGL. If they waited till 700' they would be outside of the CTAF anyway!!!
Personally i reckon that the sooner you turn X-wind (of course not bellow 500AGL) the closer you stay to the RWY, the less time you are spending when you are not gonna make it back to the RWY if your donk dies.
Common sense i say, depends on where you are and what you are in.