That's 748 props now. Randomly selected from a list of props (here now just 2 pieces, but the list of selectable props can theoretically be infinitely long). Two props each were set per polygon.
Number of polygons: 5196125.
Poser needed 50 seconds to generate the props.

By the way, the speed can only be maintained if the clones have the same textures. If you change even a small part of the texture, the speed drops dramatically (I stopped after 10 minutes). So setting random color values with a large amount of props is impossible.

Plants used:

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