I would suggest "RaggTopp" cleaner and preserver kit.

http://www.autogeek.net/racotopcakit.html

I think we get a discount there. This is tested and approved by Hartz, who Makes the roadster tops.

When I applied the protectant, I slid a clean sheet of 4 mil "visquene" (sp?) plastic under the top and over the tonneau to catch overspray. I don't know that it's needed, but one can't be too careful, eh?