I'm actually approaching this matter the same way I did CG - a max/min chart that has green for good. Bear in mind I have a single seat aircraft with no baggage. It's just the pilot and the fuel in a central tank.

I've just about worked out that I need about 450 feet from the halt to clear a 50 foot object, given my 500 foot altitude on a normal (50-70 degree) day. So let's fudge that up to 700 feet and then just say 1,000 to be safe.