probably should be dictated by the device based on its performance capabilities
it really depends on how fast the interface can assemble the list, and adding new elements.
Discussion
Also needs to be a bit dynamic, for the grid view, as it's 3 columns on Laptop/PC, 2 on Tablets and 1 on Phone. So, you need mutliples of two or three, to keep from having an unsightly gap, at the bottom.