Adherence to flux or resultant measurable parameter limits, ranges, or patterns can be achieved by directing heliostat mounted mirrors to focus on aiming points designated on the surface of a solar receiver. Different heliostats can be directed to different aiming points, and a heliostat can be directed to different aiming points at different times. The cumulative flux distribution resulting from directing a plurality of heliostats to any aiming point on a receiver surface can be predicted by using statistical methods to calculate the expected beam projection for each individual heliostat or alternatively for a group of heliostats. Control of the heliostats in a solar power system can include designating aiming points on a receiver from time to time and assigning heliostats to aiming points from time to time in accordance with an optimization goal.