I had to buy the Stickup instead of the Holdup for the exact same reason: among all of our bikes, while most don't have fenders, two we ride a lot do, so we needed the totally versitile type.
One fault with the Stickup is that it will mar the paint on the top tube, and will do so very significantly if you drive in dusty conditions at all. We solve that by simply putting a piece of heavy duct tape on the top tube where contact is made. On the bikes we transport regularly, I bought some heavy duty clear frame protection tape (also sold as car body protective material - in tapes or sheets). That does the job and is virtually invisible. Just watch it and replace it before it gets worn through.
As for the sloping top tubes, the only thing I can suggest is to try it. I think you might be surprised that they will work OK on sloping top tubes. I know they work OK on sloping top tube mountain bikes i've transported.
The top tube adapter is intended for use with the hanging style racks, not the Stickup type. I have a couple which I bought when I was using a hanging type rack (which I HATE) and they work great for that.
On the blue "women's" bike you have pictured above, I believe the top tube adapter could actually work. Put one end above the head tube on the qull stem. Put the other end on the seat post down by where the seat post collar is, and/or where the seat stays meet the main frame (seat stays are the thin metal pieces that run from the seat tube at an angle down to the rear axle). I really think that would work if just using the frame itself doesn't.
But do everything you can to avoid the hanging type. They are just an inherently fussy and poor design imno. YOu really have to be careful, and fuss a lot to keep bikes from swaying and damaging each other in transit. Note I did not say it couldn't be done, just that it is not intrinsic to the design, not intuitive how to do it, and requires figuiring, fussing, extra straps, pads and bungies to make it work.
Last edited by Camilo; 06-12-12 at 12:33 PM.