I had a similar problem in my track car. Sealed the grommets up, checked the lights, checked the spoiler. Turned out to be one of the spot welds in the panel near the boot seal either just below or above where the boot strut mounting is. Was letting in water pretty much where yours is.
Check around the boot strut mounting too. I just put a small dot of silicon on the split spot weld and not leaked since! Took me a while to find and not easy to see. It was letting in a good amount of water for such a small hole.
The roof strips prize up with a trim tool. I have a 182 that I am breaking so will try and get a picture with them removed. When I have removed these previously there was no where obvious water could leak in and it would have made the headlining damp if it did. Hope that helps
@Stink 182 @Crispy182