I have only used my Weber Jumbo Joe kettle grill one time but found this mod that looked worthwhile to do. The time I did use it I had trouble adjusting the dampers with the stock tab handle. The bottom handle was the hardest to use.
All you need to do is buy 2 1/4 -20 round head machine screws 2 ½ inches long, 4 all thread couplers and some ¼ 20 nuts. Drill two ¼ holes in the tabs and install. On the bottom tab I had to bend the tab some for better location.
This worked on my Jumbo Joe, for other sizes of kettles a longer handle may be better, if so just use longer bolts and more all thread couplers.
Top one
Bottom one
Smokin Don