I think the new roof will be lighter than the double glazed panes of glass. But it will not have a rigid aluminium frame but a timber one instead.Right, so you won't be covering it with slates, or, what is heavier, tiles like these, View attachment 234079
I once had to strengthen a roof where the previous owner had removed slates and tiled it, it was spreading so required quite radical action.
The same house had an extension which was tiled around the edge, about 2 courses and the rest was flat roof. It was no problem.
I get the feeling the weight you are putting up will not be terribly heavy so I think it'll stay up, but, wtf do I know?