FYI, here is a relatively new Service Instruction from Lycoming (S.I. 1132B) on how to perform the magneto check during run-up. Nothing dramatic, but thought you would want to know. Lycoming says they'll be incorporating this into all their Operator's Manuals going forward.
http://www.lycoming.textron.com/support/publications/service-instructions/pdfs/SI1132B.pdf
http://www.lycoming.textron.com/support/publications/service-instructions/pdfs/SI1132B.pdf