Maybe try KGC panels and paint in Bristol - tel 01179540045 - I know they have comprehensive lists and samples of old VW colours and they might be able to help.
I have use of the tool but to be honest, i have never sucessfully managed to roll an arch without the paint cracking - tried everything and would love to see someone prove me wrong - I'd just carefully manipulate it and ensure you seal the new lip etc
what car is it - might not even have to conform to emissions test ? - Make sure the carbs are balanced correctly and the engine is hot before you test it - if needs be you cold temporarily wind the mixture screws out a bit just to lean it off ?. 40's always run rich at low RPM