Good to hear the Roadsters are getting on the road in Canada...!
Sounds lovely too, I have an SD Coupe in White Silver with the Sport Pack, and think it really sets it off...
In answer to your question, the roadsters roof is a pretty hardy piece of kit. We also have a Roadster, and - rather annoyingly - have had pidgeons do their business right on the side of the convertible roof. Didn't worry about it too much, and only managed to clean it off 3 days later, but it didn't leave the slightest of marks. So no need to rush
However, some sort of rag-top protectant stuff can't harm it?! All you're gonna do is extend it's ability to stay clean!
Have an awesome time in your MINI... Hope the weather is as ncie over there as it is here in the UK at the moment... Roof down weather indeed!
All the best