At home flywheel balance....

The drag in that bearing is going to be damn near exponential with size, and it's clearly not a low friction bearing based on the tremendous cage in it. Going to some really small low friction bearings and running them dry will help you a lot. The effect of drag with that bearing will probably affect you by a half ounce or possibly more, depending on the radius that you place it, if I had to guess. I'm guessing a half ounce based on the radius of the factory holes.

How much weight to place on a neutral wheel to make it move? Well, any. But with bearing you have now, I'd venture a half ounce about six or more inches from center, at the minimum. Steal some stick-on weights from your nearest tire store, find out, and let us know! I'm curious now.

Factory balance is 19.79 in-oz, so it is at least to hundredths of inch ounces. You've not said how accurate your scale is for measuring your clay nor have you said what's "good enough", nor have you specified how much angular accuracy you expect to achieve with this method.

So, if you want to post some numbers for your expected and acceptable results, go for it.

If playdough was good enough I'd reckon more people would be externally balancing flywheels at home by now.

Personally, my feet are worth the cost of a proper balance. If you're just curious, say so and rock on.

If you're defensive, the internet is the last place to post such discussion.