Hi,
I'm not an expert in this area, but generally, specially in Windows, using two versions of basically the same thing is not advisable, as the tendency is for several of the DLL files crash on each other, when the other program loads and says that the file is already in use, or similar.
I suppose that a little trial and error is in order, but I would be careful, and if it was me, I would put one program on one machine and the other program on another machine, not in the same machine, which I believe would help prevent any possible issues.
I'm not a programmer and not sure that what I am saying is totally correct, but in my experience and in technical support for Windows since the days of Windows 95, duplication has always been an issue, and it was the main reason why (for example) the software for the video cards had to be uninstalled, the machine rebooted, and then the new drivers/software installed. Something along those lines. (W8 kinda fixed that better!)
I would imagine that today's software is smarter and better able to handle conflicts, but I doubt that any programmer would consider ... a crash course with a different version of the program .. normally installs on upgrades replace the older stuff.