Please don`t get me wrong, you can enjoy and ride your bikes like you want, that is all for your pleasure.

However with the remarks on the ride feel and performance, i think you might admit, it provides a hard time for anyone to take them at face value, when your riding that bike like a city bike. Regarding the round tube profile: The SL8 you mentioned as a comparison has mostly round shapes as well and the fork isn't deep either. Whenever you hear any expert talking about aero, almost nobody will tell you, they could just see how something would perform. I think there is a lot of confirmation bias in claiming to see how aero something is. Again, i'm not saying the slc 3 is as fast as an aero tuned allrounder or aero bike, but i argue, that you are exaggerating the difference quite a bit based on subpar parameters.

Looks good, what size do you ride?

I ride a size medium (500), 105mm stem, 380mm bars. The frame geo fits me very well, but I also had a bike fit prior to purchase to get everything dialed. 174cm, 82cm inseam.

Applying rimtape isn't hard, take it as an opportunity to learn. Just take your time with it. There is enough tape on a roll to be able to mess up.

It seems like xiamencarbonspeed is gaining some heavy traction. Even on a german forum more people are looking into them and are buying wheelsets. I hope xiamencarbonspeed can keep up their good quality to price ratio. Price hike upcoming with the increased demand?

Got my first ride in, 2h30 Z2 at 0°C and wet roads, so can't say anything about the finer riding characteristics, but overall I like the wheels very much. Running 28mm front and 30 rear, which measure 29mm and 31mm respectively. Both tyres at 4bar/58psi, setup tubeless. That is the 50mm deep 29 rim outer 22mm inner width btw.

First impression is that the wheels strike a good balance of stiffness and compliance. The ride is firm, but not harsh, road vibrations are kept in check. Obviously that combination of tyre width and inner rim width doesn't provide a plushy ride, but they feel non fatiguing to me with my setup. Road conditions here are pretty bad and I made an effort to not avoid road cracks etc.

Cross wind stability is alright. Large close passing cars do create a small tuck, but I also tend to have a light grip on my handlebars. Steering always corrected itself and I didn't feel the need to preemptively brace myself for any passing car.

Got my D50CU-28 T1100 in the Mail. Wheels look great, packaging is very good and overall quality seems to match expectations.

One caveat are the actual rim measurments. Actual measurments are 22mm internal and 29mm external instead of 21.4mm internal, 29,2mm external.
With the wider internal and narrower external width a 28mm gp5000 s tr measures 29mm and sits flush with the rim profile, so no rule of 105% to achieve here, if your don't want to have a 25mm tyre, which most of us certainly will not want. So in some way the rim profile is neither here nor there, neither fit for narrow nor really fit for wide tyres. I will get on with it, but this difference to the advertised measurments is the worst difference you can have in a rim profile. Both rims measure the same btw, so i don't think this is a unit variation problem.

Measurements done with a digital caliper and at multiple locations.

I used to use a speed sensor but DCrainmaker had a great article basically proving that GPS accuracy just as good as a sensor so I took it off my bike to save a few grams.

On my Bolt V2 with it's mediocore gps this isn't my experience. A speed sensor is vastly superior for me.