Mount a balcony box hanging from the windowsill

[Turbopumpen]

Hi in the heat,

Going to replace a shabby balcony box (see pictures).

Planning to replace the wooden pieces with galvanized edging "wide model." Pop rivet to a new balcony box and screw into the window sill with sheet metal screws.

Good or *nus?! I'm a bit worried about the weight, soil plus water weighs quite a bit 😬

Grateful for any feedback!