The emphasis on water and wind noise leakage I believe, should be at the rear edge, where the tilt and retract actions occur. Since the tail end of the glass panel has to perform 2 functions, therefore the height and gap setting is crucial to prevent leakages. The edges on the glass panel are a furry type of sealing surface mounted on a rubber moulding aroung the glass panel. This type of sealing surface gives good overall dirt absorbtion and resistance to water & wind intrusion into the cabin. Of course, such set-up requires some maintenance (covered under Sunroof Maintenance section), or the sealing ability is compromised.
This is a separate photo shot taken as close-up, showing the gap and height alignment that I did after the new car was taken from the dealer's lot. Initially, the glass panel height was slightly below the chasis roof line, which puts a risk for water leak (allow me to elaborate later). This setting is tested to >110km/h in the heavy rains ( I will not disclose the actual speed, just in case the traffic police is reading this blog ). For safety purposes, use Rain-X on the windscreens to deflect the water to ensure a clear view of the roads, and ensure at least 80% tire tread if such need-for-speed arise. Also note the curvature of the roof line, matched by the glass panel, with the apex at the center.
Another photo shoot of the entire rear glass panel gapping.
This is a view of the sides gapping. The gap is largely determined by the chasis and glass panel fabrication dimensions. Alignment is only limited to ensuring a proper centering during the bolting, or in some cases, the centering alignment is totally flexible with no alignment screws / bolts.
A view of the front gapping and height. As mentioned earlier, The glass panel rubber moulding height must be at least the same height or higher than that of the roof line. This is to ensure water flow AROUND the sunroof rather than over or accumulating on it (if the glass panel is below the roof line). Secondly, the furry seals on the rubber moulding is below the surface, and need to come in contact with the sealing surface of the chasis cavity. Lowering the height of the glass panel thus increases the risk of water accumulation at the gaps and leaking into the water drip pan below. Coupled with speed and stop-go-movement, it will result in spilled water into the cabin. There are also some arguments on "drainage" piping issues that I will address in the "Sunroof Maintenance" section, as the drainage issues can be easily checked and be verified.
This photo shows the side view of the "Tilt" and "Retract" mechanisms, that can be readily seen without removing any cover panels. Pictured is the "rest" position of the sunroof (closed position). Note the round stub close to the spotlighted area. This is the index for raising the sunroof for tilt and lowering the sunroof for retraction mode.
Pictured is the round stub at the "retraction" mode. This position of the stub lowers the glass panel for retraction into the cavity between the chasis roof and headliner.
Pictured is the sunroof at the "Tilt" mode, with the round stub and arm at the raised position (spotlighted area). Retraction mode will be in the opposite direction movement of the round stub.
This is the exterior view of the "Tilt" mode so there is no confusion as to what it does. OK so far ??
Pictured is a view of the mechanism. Note the rear adjustment bolt (in blue) that is meant for final stop height for the glass panel rear end (driver side).
A more detailed view of the same bolt from outside of the car, as we will be focusing more on the details of glass panel height adjustment.