I've had my T-panel off the car so long I've misplaced the screws, including the ones that hold the slotted fiberglass trim that retains the back edge. I had #8 sheet metal handy because I had to replace the ones in the front edge bracket. But the #8 seems too small for the panel itself (although they do grab). And it seems like the rear trim might be #8, but perhaps machine screw not sheet metal. The sheet metal ones caught, but didn't thread and I didn't want to force them.
TIA
Josh