Hi, sorry for the slow response. Here's how I did it:
Scaled down and blurry solution (all in OBS)
1. Add a video source
2. Add a Syphon Client
3. Move the Syphon Client window to the upper right corner of your canvas and scale it down a bit
4. Scale down the video source window and move it to the lower left part of the canvas. You can now scale this up or down and see the result instantly in your Syphon Client window (in the upper right).
5. If you want to you can add filters to the video source to try to compensate for the blur, such as adding sharpness and using some color correction.
6. If you get grey borders on the sides of the video, you can solve this by reducing the size of the OBS window so that the video covers as much of the space as possible.
Hope this helps a bit. Personally, my main goal was to get the video into CamTwist, so I have decided to not use SyphonInject for now and instead use the Desktop+ feature in CamTwist to capture the entire OBS window instead (which only works if you have a second screen).