I purchased a hardtop recently and have been experiencing the same issue reported by JackB1 near the start of this thread. I somewhat regretted my purchase until I followed the advice laid out above; thank you all for writing up these guides and putting in the effort so that they are accessible to this day. I took some photos along the way, hope they could be of use to someone.
So the way my hardtop used to look at the front is as below, where the middle section interfaces well with the top of the windscreen, but a gap seems to open up toward the outer edge. Also worth noting, I only had this issue on the driver's side so I only needed to address that side.
Toward the back of the hardtop, behind the driver's window I could see that the gap is more than the 5mm as recommended by the guide further up this thread.
Therefore I followed the guide above to bring this gap down to a level akin to the passenger side.
1. I undid the hardtop front anchorage point with the allen key;
2. I removed the trim panels next to the headrest to access and undo the rear hardtop anchorage points;
3. Next I removed this plastic ring. In the image above you'll see that I skipped ahead and did that already, apologies for the continuity error;
4. I disconnected this electrical connector for the window heater;
5. Now began the actual height adjustment. I loosened the locking nut (the upper one) so that it spins freely;
6. I turned the lower nut to adjust the installed hardtop height. My hardtop gap was >5mm, so to lower it I loosened this nut 1.5 turns (wound it upwards);
7. I re-tightened the locking nut to finish.
The adjustment was now done, so I re-installed the hardtop by tightening the front and rear anchorage points to check how it sat. I'll put further images below, as the webpage is no longer letting me add photos.