I used a short screwdriver bit and turned it with a 1/4" wrench while pressing down with my finger. It wasn't easy, but it worked. A gearwrench would have made this much easier. I had to retrieve the bit a couple of times from the crack with a magnet. Bonus...while digging around next to the windshield, I found a 50 pence coin! Thanks LR!!!
My dash was curling badly, so I put a few screws in prior to installing the dash repair kit between where the kit holes were going to be. FWIW--I used short drywall screws.