Achla Designs SFB-01C Clamp-On Flower Box, 6" Deck Bracket, Black

Would this work on a brick window sill? Also, what is the maximum weight it can support?

What sort of clamp can I find to hold a flower box onto a second story window sill that is cement? It’s 4” thick.

What is the width of the smallest planter these would hold? 10"?

What bracket or clamp would secure a flower box on a 4” thick cement window sill?