Jesus, dude, you're really invested in this and your benchmarks.
Here is a well-known benchmarker comparing the two models using the alternate gpu
http://barefeats.com/rmbpc2.html
Granted, that is testing games, but its a bit of a proxy for us here. Have you ever used Adobe AfterEffects? I am telling you, the video pro apps WILL perform better with the discreet GPU option. The original poster was even thinking of a 13", so he clearly asked for advice and I'm giving him the right advice. Its not a good idea to think the two models are the same for his needs because on some raw computational basis on paper they look the same.
Even if they were, as is pointed out, there is NO financial savings by buying the irispro only model, as by the time he gets the required ram and ssd, they are the same price
As for these apps supporting OpenCL, I think you need to dig into this stuff a bit more to understand what is going on here. Here is Adobe support explaining to someone how the software needs to be written to take advantage of specific GPU models in order to use OpenCL. Its a little dated in the specifics, but I think you can assume that it apply here to the nvidia cards. And you can assume that the Adobe software will add the 750, but I wouldn't assume it will add the IrisPro. Also, even if it can use OpenCL, CUDA is faster in the real world Adobe
https://forums.adobe.com/message/5081640
Lastly, here is a discussion of the issue, including your benchmarks, on the REDUSERS forum. Red is a manufacturer of a well-loved digital camera.
http://www.reduser.net/forum/showthread.php?107852-15-quot-late-2013-RMBP-intel-iris-pro-graphics-vs-nvidia-geforce
You can choose to argue with me because I haven't given you a spreadsheet, or not. But the original poster clearly asked for advice, and my advice is that he would be selling himself short on performance, for no financial gain, by going IrisPro only.
let me quote the reduser who actually used both in the real world.
"I just did a side by side comparison and the difference is pretty dramatic. A 30 minute render in Resolve takes 2-3 hours in the Iris only version.. not to mention tracking gridns to a halt in the lesser version. I was really shocked when I saw what was happening."