> The over-bright issue I previously mentioned is there - but only when the saucer > moves vertically. If it moves horizontally, then it is as it should be. > > Is this a limitation of some kind?
This is due to the phosphor effect. In the vertical the saucer does not have much black spaces compared to the horizontal. The phosphor effect fills these small vertical spaces and the saucer appears brighter if it moves vertical.
Setting phosphor r,g,b to 0.25 instead of 0.5 should help.