I would bump number 6 to the top of the list, then erase the rest of the list. The only time I've ever missed a shift on the 919 is when I'm shifting too timidly for the gear to properly engage. You don't have to abuse it, but a firm push is necessary for proper engagement. If it ain't broke, don't fix it!
2002 919 40,000 miles
"racing is life...everything else is just waiting"