I'll give it a try, thanks.
The problem is that adjusting one variable demands adjusting several others. Altitude, speed, distance, bank angle, all these are linked and interfere with one another.
If the ceiling is low, and for instance if the area is somewhat mountainous then you would need to reduce the altitude, the circle diameter, hence adjust the speed and angle, and be killed because you lost time in regaining line of sight..
franzy666's post in How to Perform a perfect Orbit on Target? was marked as the answer