I do not agree -not to be contrary but------------
On single cyl engines - balance does make a difference, as does eliminating tip flex from any prop
APC is pretty dang good-but they do -and I don't know how miss on some .
On th tiny electric APC props -(8x3.8 SF) a rebalance does show marked improvement on some motors
th balance may only be 1" of invisible tape.
Typically tho the unbalance is not along th blade - but due to the centre being oriented incorrectly - vertically .

These sometimes require careful work along the hub -or a rebore (file off center then bore then resize).
On my big engines (running props up to34") -I really make certain the prop is dead on.
The unbalance in some singles is so bad that the prop can be used to slightly correct things -but I don't use those engines .