To clarify

Putting in spinner weights = BAD IDEA
Putting in a weighted prop hub = NOT a bad idea.

The latter can fit under the spinner and mounts on the drive shaft.
They come already balanced, and the additional weight helps to keep your engine from dying out at idle.

Since you are putting weight in as far forward in the plane as possible, the increase can have more of an effect than forward fuselage weights.

However also consider trying to move your engine forward.

A .5" forward movement can be the equivalent of adding 2-4oz of weight to the nose.