Cannondale Supersix Evo HI Mod headset

Hi. I’m aware that there have been many discussions on how good / bad the Evo headsets are, but bearing in mind the success of this frame over many years am inclined to believe I just might be unlucky. Anyway, I’m not getting an answer from Cannondale at the moment so wondered if any of you could shed some light on the question I sent them below particularly if you can see the differences between the headsets.

“In 2016 I had my 2015 Cannondale Supersix Evo HI Mod frame built up with top spec components only to suffer various headset problems. Recently, local shop replaced headset with K35028 headset. I’ve now got to the point I won’t use it due to very strange vibrations descending on rough surfaces but not really ‘full wobble’. During this time this has happened with 3 different wheelsets. I notice from your Cannondale Spares Headset Finder that this might not be the right headset and it should have been replaced with K35068. So, could you tell me whether this might be the problem? What are the differences between the 2 headsets? I’m more than happy to buy a new one from you but just want some confidence it’ll fix the problem as my dream bike has turned into a nightmare.”