Regarding that, in the past I said mine gets a few drops in the silver rails, and towards the back of them it looks like nothing's been through there in ages (dusty). I said I get a bit around the little holes at the front corners of the rear sunroof. Anyway, the other week I had the front sunroof on tilt, and got an LED torch and tried to look down in the innards, towards the front of the sunroof where the tilt angle goes to nothing. I noticed some drops/water around the FINAL exit hole at the front of the front sunroof. And some where it must go through the hole at the front of the rear sunroof, and into the side cassette front one. There was some in a small trail in the side of the cassette too. More on one side than the other. I got an artist paintbrush and kind of 'cleaned' it and it was a touch slimy. Prob never been touched in 14 years. If you look in the sides of the front roof, there are two holes (on each side). One which connects to the the rear sunroofs front corner hole, and the other at the front of the front sunroof, where it must then drain out. So in summary for front drain exits, I reckon the process is any water goes through a tube between the rear and front sunroofs, i.e out of the rear sunroof hole, through a tube, out through the hole at the back of the front sunroof, along the side of the front sunroof cassette, then out the final little hole at the front of the front sunroof, then via a tube to exit somewhere by the front wheel I expect.
For reference my Elgrand is parked on the flat on the drive, but with the Elgrand's roofline having a slight front angled bias, probably explains the front rather than rear draining.
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