I have a Felt Z4 carbon bike. I have been told I cannot use racks that require eyelets or whatever and that my best option is a seat post rack. Most of these have about a 15 lb. limit, but that should work for me. I have read about Giant, Delta, Blackburn, Topeak. They all seem (on paper) to be variations of the same thing. I also found the Arkel Randonneur Rack which primarily attaches to the saddle rails with a passive support on the seat post. This looks like it would reduce sway. Can anyone give me advice on this?