in my post I went back & forth on which way (larger or smaller) was right for my line of thought & I'm thinking a smaller one would make the speedo turn faster, overdriven (read higher) & say for instance, show 68 when you are actually going 65 so you would then slow down a bit as opposed to a larger tooth one that would turn/read slower & show 65 when you are actually going 68 & you would think you were legal when you're not.
I always get fancy/complicate things, YMMV.