I'm inclined towards doing some footwork on this; but before investing any work I'd like to hear if it's something really trivial, or an absolute fool's errand. . . .

Any thoughts?

I'm still on a 32-bit platform myself so I can't really help; the only thing springing to mind would be trying to recompile the C++ RDNZL.dll with a win64 platform target and try loading that instead. I have no idea what that would do, though. Regards, Iver