Switched from iteration value based coloring to 'Dwell value' based coloring, which is a ratio of the iteration value to the distance from the origin.  This allows for smooth coloring using float values.  Still compatible with old discrete coloring method and runs, but need to change color calculation method using some sort of index table to colors which can be mixed based on a ratio, with the ratio being the decimal portion of the floating point 'Dwell value'