You ask about solexx glazing.
Pitched roof greenhouse.
Thus the pitched model will be the right kind of roof of greenhouse.
The slope of such a roof will be determined by wind and snow load on the structure as well as attractive appearance.
A greenhouse roof needs to have enough slope to prevent leaks and dripping condensation.
A lean to greenhouse extending 6 from your house needs a minimum 8 of height with an additional 4 for each additional foot the greenhouse extends from the building wall.
If you design your internal structure according to local codes however you will not have any difficulties.
This will shed snow under most conditions but with twin wall coverings it is not always the case.
In addition the angle of inclination is determined using a specific roofing.