How to build a balcony on a metal roof?

[Ådala]

Yes, alternatively the gutter one step down. Then you can attach the posts above.

Yes, it doesn't feel like a good solution to have the posts spaced outside the gutter. I've also never seen a balcony with a similar solution, so I feel unsure if it's really a good idea...

 

[GoForIt]

No, that's not what I meant, but down with the gutter one step.
Is the overhang on the metal as pronounced as the picture shows?

 

[Ådala]

No, that's not what I meant, but down with the gutter one step.
Is the overhang on the sheet as large as the picture shows?

The overhang is about 4-5 cm.