I also wrote a similar article about the Dell U2713HM monitor.
I was really hoping that there would be a variety of ways of getting a stable connection to this monitor, in the end I only found one that was the most practical.
For the first three tests I used the Apple Multi AV adapter, these are the results:
This was what the HDMI port connection flicker looked like (it's really quite unusable)...
Even though the MHL port only gave a maximum of a 50Hz refresh, it was quite usable. Considering this is not a CRT, even a 30Hz refresh would be OK (which this method of connectivity also supported).
My next lot of tests were done using a USB-C to mini-DP adapter that I bought from eBay.
So the most stable connections were either with the Multi AV adapter to the MHL port or the mini-DP adapter to the DP port. In my opinion the Multi AV method is the most practical since it gives you the option to have both power and a USB 3.0 connection at the same time, plus you don't need to connect a second adapter. That's the method I'll be sticking with.
If you've tried other ways of connecting this monitor via USB-C let me know what worked for you.