Anyx64 version of the C++ Redistributable between 2008 - 2012 will work with 64 bit installer versions of Vegas through Pro 14, maybe later. The no-brainer clue, of course, is that x86 C++ Redistributables will not allow system registration of files destined for installation in the "Program Files x86" folder.
As proof, I successfully installed Pro 14 and MSP 13 on a new Win 10 box, but only after installing Pro 8.0c, of which the installer downloaded 2008 x64 in addition to 2008 x86, because it was the first Vegas to include a 64 bit .exe (which fell from grace rather quickly). 2012 C++ is not on this machine, and the only new one is 2008 x64, which allowed MSP 13 and Pro 14 to install after multiple previous fails. Go figure.
Here is the Microsoft 2012 Redistributable download: