Have you seen Luke's tips and tricks on this video? Starts at 12:28

I do not think he says anything about shifting issues, or tricks. In any case, it seems that I might have messed up the shifter housing while installing it through the internal routing handlebar, because I have tried with an external cable and it did not take long until I got it right. After putting it back through the internal hose again, it does not shift properly (going up in gear, so releasing tension, which makes sense). So time to buy some decent shifter housing and try to install it without messing it up!

/Xtract

OK, so I fixed the situation pretty easily. I bought the Deda compression ring 45 degrees:



First I sawed the largest part of the top (circa 2mm I guess) with a hacksaw and then I ground the top down a smal bit at a time with a Dremel tool till it was at the correct height to compress correctly but also not leave a gap between the frame and the headset cover (there is still a very minimal gap say 0,5mm). I also used a Deda 70mm expander plug to get a bit more grip while tightening the top cap. No play anymore and a very cheap solution.

So you basically had to remove two mm from the upper side so that the spacers can lie flat? I am trying to imagine what you have done, as after building up mine I think the fork still has some play. Attached a picture of my build!

Also, I think I have mounted too many spacers, but I do not want to remove the cables from the handlebar (what a pain!). I assume spacers like this would work?