I had ThrottleMeister installed on the Helibars. The bar end bolts go into a female thread inside the bars. The bolts were too short at 60mm (as the female thread inside the Convertibars is much deeper than Helibars)so I had to get another 2 M6 - 1.0 thread x 80mm flat head stainless steel cap screws for them to reach the thread. 80mm is the longest bolt available and they fit just fine.
80mm is the longest bolt available in the world with M6-1.0 thread. The 80mm bolt just barely reached the female thread inside the Convertibars to reinstall my ThrottleMeister bar ends. Just barely. May be the ThrottleMeister heavy bar ends are longer than stock, as I don't have the stock bar ends anymore to compare with.