Your nickel strip has to safely carry the current of the parallel group. That depends on: Examples of popular 18650/21700 cells: If you have 3 cells in parallel (3P) and each cell can do 20A, that group could see up to 60A.
The calculated weight of ballast is placed into the pod after that the panel is fixed to the wedge. In our experience on average tends to be 90kg per panel. This is can be an unsuitable amount of weight for some flat.