Here's my thoughts on all this balancing (I hope I stir the pot on this one)!
I used to try to spin up the blades and add weight and go back and forth....adding weight, taking weight, chasing my tail like a dog!
Now what I do, is just get out my most accurate scale and weigh each blade. If one is off a little, I just add monocote. If it's off a lot, I add some alluminum tape, normally at the center of the blade. The problem with the Kellett kit is it uses the sig airfoil and I've had some pieces of that weight 20 oz and the next one weighs 80 oz!
So just try to get each blade weighing the same...however you can and call it good.
Did you get the video that came with the kellett? If not, I posted it here: