Recommendation Weight on Top of Speaker

Whatever you do, don't let your signif other put a plant on top, no matter how "good" it looks or sounds!!!

the speakers are fine with nothing on top. the sonus faber cabinets are superb and solid

Weight can be beneficial when utilized properly. Exact amounts must be determined by experimentation. I happened to own some old VPI bricks which were and are one of the best solutions for speaker dampening. Mapleshade heavy hats are also excellent and look cool as well!

Not too argue.
The speaker pistons create vibration.
Vibration is not helpful for good sound.
Mass will absorb vibration.
A leather bag of lead shot and sand will work well.
As heavy as structures allow;in this case there's
no such thing as "too much of a good thing".

one inch granite. should cost no more then $45 a square foot. I use such on top of ProAc's. Did improve the sound.