After removing the hex heads, I used a counter sink so the heads will be level or below the level of the fiber glass.
Here's my quick check to make sure the head of the screw won't stick up too high. I flipped the screw upside down and that gave me what I wanted to know.
The red arrow points to some grunge that is extremely miserable to remove. It's old caulk, and who knows what else.
Scraping takes less time than sanding with 36 grit, but it's still not fun.
In case you are wondering, this was a couple of hours worth of work. I know, it looks like it should have taken about 15 minutes. I wish.
I still have probably about a dozen more screws to remove and replace, and I'll probably have to get on the roof to access them.
