When I got the car, the top leaked quite a bit in heavy rain. It's the reason the floors were rusted out - frequently wet carpets.
I made a cover for it out of some used boat shrink wrap :
There are some cracks in the vinyl where it folds, but I discovered most of the water was coming through the stitching along various seams. So this summer, I spent some time carefully taping & applying a bead of black silicone over the stitching.
Now the only place it leaks is around the weatherstripping above the driver's window. Current solution!