it will stop in a vertical position. My Maule did this, my C150 did
not.

It is not possible to align a two-bladed prop with all the crank throws
of a six
cylinder engine.

My 172M (a different one from my earlier posting) stops with the prop
@ 45 degrees, and is at TDC @ 135 degrees.

I don't think a 6 cyl engine has any reason to be sensitive to prop
orientation when it comes to smooth operation, although I can
appreciate that they might for some other unknown reason.