My guess would be that it is not your weatherstripping but a clogged drain hole. Where is the leak occurring?
If it is near the left and/or right front edges of the sunroof, one or both of the drains are probably blocked. If you open the roof and look closely at the corners, you will see small holes. These allow water to drain from the sunroof assembly through plastic hoses and out of the car near the rear of the front wheels.
I have used plastic trimmer line (Weedeater type line) to open these drains. You can also use air pressure to open them up. You will know when you have them open when you can pour water into the small holes and it will drain out at the bottom of the car.