The halo in one picture
A wide halo means a cheap cast; a halo tightened to the dashed marker means the maximum. The difference between the two extremes is more than six times the points, which is why patience beats speed on this board.
Reading the counters
Points and casts together tell you the average value of a cast. Anything above thirty means the timing is right; below twenty means you are clicking on sight rather than on the halo.
A practice routine
Spend one shift ignoring the score entirely and casting only when the dashed marker appears. The number at the end is usually higher than a shift spent hunting every shape.