I still haven't balanced the 8" tires, but I got new tires for the P200, so figured it'd be a good time to balance the hubs and rims/tires and see how it goes.
My front end would shake if I let go of the bars going down the road by my house and the front end would shake when putting on the front brake. It felt fine at speed though so I didn't think anything of it.
Well, after balancing everything, the front end doesn't shake - it's rock solid letting go of the bars going down the hill.
I put about 9~10 grams on each hub, and a boatload on each rim/tire. I was surprised how much weight each tire took to balance.
And yes, I affixed the weights with shoe goo.

Whether it makes a difference in actual real world riding or not, I'll be balancing all my rim/tires from now on. I'll take any advantage I can get in making the scooter roll smoother.