I have very similar usage for my MBPr mid2014 GT750M.
Thanks to goalgues's script egpu setup on OSX 10.10.5 was flawless.
I am using Akitio box, Zotac GTX970, CHIEFTEC Smart Series SFX-500GD-C power supply for GPU and Akitio.
It is working even on restart. With 400W cheap power supply I have to hot plug Akitio so I have changed power supply.
My main goal was to using it for DaVinci Resolve, but gain over GT750M in rendering is only 3-6 fps (usually only 3fps). But playback of 3.5K Alexa 4444XQ footage is jumpy, stuttery and eventually stops. Without eGPU, playback is steady.
What is your experience with DaVinci Resolve in OSX? Can we compare rendering times and usabilty?
Is enyone else is willing to try transcoding on various setups with CUDA acceleration (or Open CL) in DaVinci Resolve so we can compare.
Davinci Resolve is free and it is very easy to do testing if we use same footage and same export encoding settings. I can provide guides.