questions about v1 differential for revo (g2r)

thanks again that calculator is freakin sweeeeet, i have nobody but this forum to help me, my lhs is not interested. i am so appreciative of this place.

so is the Spur/Pinion Reduction Ratio same as final roll out?

my current choices are 2.55/1 at 34 mph
3.19/1 at 27 mph
which is the most efficient for the electronics? it's about 90 f here