Emergency closure roof

Hello I’ve been driving a 107 for 22 years, and I bought a R230 some time ago The following question concerns me since I’ve been driving open with this car: If the aut. closure of the roof fails: How fast can you close the roof manually? Does that work alone? Does anyone have real experience with it? Does one possibly have a tarpaulin in the trunk for the absolute emergency? Thank you SL-Helge