Kubota V1902 front crankshaft spline?

[ishiboo]

I'd like to add an electric PTO to the front crankshaft of my L3650, as well as install a magnet for a hall effect tachometer, since the mechanical tach is awful.

Any ideas what spline it uses? It's the "fine" spline of the two, but I have no idea what that means or where to find a compatible part for it!