Arno,
When I bought mine I thought the channel seals that were included were too stiff to lay down nice, but once I started working them on, they fit really nice. Like I mentioned before, I used one of my original moldings and both of the new seals and they worked great. If I remember correctly, they did appear to be two walled cause they looked exact inside the channel. I also installed a set of soft seal rubbers and they took a little work to slide on, but all in all the fit was pretty good. When I wash the car I don't blast pressure right against the windows but so far no leaks at the seals or weather strips. Also, I did buy my set about a year and a half ago, thus the price increase. Hopefully some others will chime in on their experiences. Good luck,
Dan