... uuuh, I must surf deep in my brain ... long, long time has gone since I made it (and acutally my sunroof is in the highest area of my garage, stored till mounting).
So I try (no obligo!) => the 4 main-rods are running in the alu-profile "under the roof", contoured and following during opening/closing always along the roof of the car.
The 4 small rods are fixed with a helping-arm on the main-rod and they are runing free (outside the profile). This "secondary rod" will only press the canvas to the roof, if canvas is in closed position. You see, that the construction of the helping-arm will adjust these secondary rod (the free running one) parallel to the main-rod in closed-position.
The general function is => First rod in the profile, second out, third in, fourth out and so on. With this arrangement the canvas can go upstairs during opening and it will lay "press" on the roof, if you close it.
All rods must be stored in a "sack-hole" of the canvas. Because of the sharpnes of the rods all rod-ends must be armed with a leathercover on their end, otherwise your canvas will be destroyed inbetween minutes.
On the end of the canvas (over the rear window) the complete canvasconstruction must be fixed on the roof with Sikaflex or onother gummed adhesive material. The screws alone may not fix it enough!
Sorry, canŽt explain it more clear ... hope this will help you. If necessary, I can make detailled pics from my roof or/and make a scan from my freehand-sketches.
good luck during mounting your roof in the correct way, give please reply from the result
hans