Back to Vinci's roof writeup. . .
If the sealing frame and tack strip are incorrectly replaced/installed, your roof will leak into the trunk. The butyl sealant is between all those pieces, in two areas. Not enough=roof leaks. Incorrectly installed=roof leaks.
The sandwich is carbody<>sealant<>sealing frame<>sealant<>tack strip
If you have a new top, and it leaks, the butyl sealant is likely the culprit. It should have been replaced with the top. It is a simple RV style sealant/bedding compound. Comes in rolls with a paper tape on one side. Cut to length, stick it on, peel off the tape. The TIS instructions say that in the curved corners to use double thickness. I think the spec is for 1/8 x 3/4 inch butyl.
You *might* be able to fix the leak with a flowable silicon, like windshield silicon, but I have no idea what that would do to the top if it gets into the wrong places, or if too much gets in there. You possibly could end up with hard spots or some such.
You would have to flow it into two places. The body<>sealing frame area, and the sealing frame<>tack strip area.
The correct fix would be to unbolt the sealing frame and tack strip, and the 4 top bolts, and remove the entire top from the car. Correct the problem, and reinstall. 4-6 hours, maybe?