Round and Square plates
Here are some tips to help you to choose:
The square shape:
Advantage: adapts to most of the wooden roof structure (frameworks)
Inconveniences: is heavier, not good looking, may be cut to size on site
Conclusion: Better to use when there is a hidden framework.
The round shape:
Advantage: more good looking, adapt to concrete slab
Inconveniences: is not adapted to framework
Conclusion: Better to use when the suspension plate will be visible in the finished room.