RE: General rule of thumb....?
fingerz---another reason they say to hunt high in the morning is because the thermals begin to rise as the sun comes out. By hunting high, you avoid spooking deer due to your scent rising from the bottoms. Hunting low at night is preferred as the earth cools and pushes the thermals ( along with your scent) back down the hillsides....hence it is better to hunt lower as the day begins to cool.