Just a little suggestion regarding finish care in general, not just for the convertible top:

Preventative maintenance is always much, much easier than trying to restore something once it's gotten bad. Regular applications of either the RaggTopp or Meguiar's protectants will serve you much better than waiting for the top to get so bad you end up trying a dozen things to try and restore it. Same goes for paint, rubber, leather, etc.

People always complain about how much work it is to wax and detail their car, but they complain even louder when things deteriorate and then a simple wipe on/wipe off product won't magically restore things.