You are welcome Harmy :-)

Rendering at 8 bit is fine since the finale encode has to be 8 bit anyway, at least if it should be playable on hardware players.

The color space stuff is complicated for me as well. The thing is that there will always be a conversion to YUV420 somewhere. It either happens when rendering in Premiere or in the encoding process.

Can you upload a sample of the scene you posted screenshots of? Render it with UtVideo RGB. Output colorspace should be BT.709 or Rec.709 if that's available.