Although I'm not allowed to use things that result in burning (or sharp things, either!), an idea for transferring the pattern to the cork MAY/COULD be found in the fabric store. They have tracing paper, that when placed between the cork and the pattern, can be traced with a ball point pen, or other fairly sharp object, on to the cork. Then the burning tool could be used to carefully follow the pattern you've traced. Hold the tracing paper/pattern in place with painters tape. I'd suggest practicing on a piece of flat cork, before trying on a "real" grip.