Remove the drip trays, they hold the sunroof in (along with the sealant) they will probably still leak even if you re seal the roof, it's how they are designed. You are as well to look at the front corners of the tray where the drain pipes are. The little plastic trays leak and the plastic becomes brittle and the pipes break off.
Once you drop the tray make sure the little plastic drain pieces are well sealed that the pipes aren't blocked.
I've done a few of these, it's a well worthwhile job that needs doing right.