This is always a bit of an amusing request to me.
The synthy score is simply a measurement of how many of the images were able to be matched to each other. The synther doesn't know this until the very end of the synthing process. There is literally no way to know how many of the images will match each other in 3D until you have matched them to each other in 3D.
It's a bit like making up a complex equation that no one has ever calculated before and then asking a math professor, "Please tell me the answer before you solve the equation.".
Don't get me wrong; I have every confidence that the synthing process can and will get faster, but I haven't seen anything even in the research papers that shows a dramatic speed improvement yet.