"5120 x 5120 at 60 fps" here is why that's overkill. If you start putting dots on a sphere you can go in one direction turn 90 degrees, put 5120 another axis. However, if you tile like that with 5120 x 5120 you get a lot of wasted pixels at the poles.
If a 5120 pixel Radius is fine... then Radius of sphere = 2 pi * r, and Surface of sphere is 4 pi * r^2. So 5120 / 2pi =r substitute for r > 4 * (5120/2pi)^2 simplify > (5120)^2 /(pi) ~= we need ~1/3 aka 1/pi of 5280^2.
However, I suspect you actually want more than 5120 pixel radius.
If a 5120 pixel Radius is fine... then Radius of sphere = 2 pi * r, and Surface of sphere is 4 pi * r^2. So 5120 / 2pi =r substitute for r > 4 * (5120/2pi)^2 simplify > (5120)^2 /(pi) ~= we need ~1/3 aka 1/pi of 5280^2.
However, I suspect you actually want more than 5120 pixel radius.