Hello!
The glass will need to be laminated. Then, whether it also needs to be tempered or heat-strengthened, I'll leave it to your glazier to decide. I wouldn't go over 900mm c/c (thicker glass required) and lengths of 3500mm are impractical/cumbersome/fragile to handle, and you might have difficulty finding a supplier. Regarding the slope, I would recommend you have at least a 7* inclination (the same as what polycarbonate sheet suppliers usually recommend), otherwise, there's a risk that the wind will push water against the house. Note that for any installation, it's highly likely that a crane truck with a pancoce will be required.
Best regards, fremax