Factory bolts are long enough. To mount the the handle through the hole, I was close to LJ Jim's measurements.
For mine this worked out perfectly: I made a vertical pencil line 7 1/4" (measure on the straight/flat side that is closest to the windshield) from the end of the tab that tucks into the center trim piece. Then I measured 2 inches down the line (again measured from the straight side that sits closest to the windshield towards the curved side), and made a center mark there.
Drill a 1 1/2 inch hole saw at that point. After drilling install this grommet: https://www.amazon.com/gp/product/B06XKH4Z89/?tag=wranglerorg-20
For mine this worked out perfectly: I made a vertical pencil line 7 1/4" (measure on the straight/flat side that is closest to the windshield) from the end of the tab that tucks into the center trim piece. Then I measured 2 inches down the line (again measured from the straight side that sits closest to the windshield towards the curved side), and made a center mark there.
Drill a 1 1/2 inch hole saw at that point. After drilling install this grommet: https://www.amazon.com/gp/product/B06XKH4Z89/?tag=wranglerorg-20