Avenger

Hi, first off I want to say that i am quite impressed with many of the builds here! So much in fact, that I want to construct my own. I am using a mid 2012 MBPR with the 650m. 1. Considering that it only uses TB1, does it even make sense to use an eGPU or should I wait for TB3? (No point in swapping the 2012 with a 2014/15 one I think..) 2. Could I somehow operate the eGPU with the internal display? (The obvious answer is probably no, but isn't there a way to EFI boot Windows, make the Intel HD visible, disable the 650m and switch between eGPU and Intel HD?) 3. EFI version of Windows - Which Windows would it be? 7,8 or 10? Assuming I can even manage to install any kind of Window via EFI, would it even fully work? I heard that for some sound doesn't work... 4. The 2014/2015 version of the MBPR with the Nvidia 750m or the AMD R9 370m boot to Windows not via Bootcamp, but via EFI, yet they don't support Optimus? 5. If Optimus is not going to be available on a MBPR with a dedicated gpu, the next Mac I buy would have to have an Intel Iris Pro at most, right? I hope you guys can help me! Thanks!