Convertible or ragtops

Hey does anyone on here know how to make a convertible top. Say im converting a hardtop car to a convertible and i cut the roof......how can i make something to lay on the back so it looks like a convertible top cover. Anyone??? thanks guys

ps. This jersey weather sucks. I have 2 models done and all i need to do is paint and polish the bodies. Sittin at my desk for 2 weeks cuz of this damn weather.

THe only thing that i would say u could do, would be to Use masking tape, and try to make a "soft" top look. i read that in a magazine,