I just got through balancing 10 of my tires (8 for the two Mini's and 2 spares). Vibration is energy, up and down movement requires even more energy to cancell it out. as superman says "A lot of little things add up to a big thing" Guys this is racing, look for every and anything you can find. some of our tracks are really nice and flat and not having to fight a wheel jumping up and down and keeping the contact patch on the ground may be worth the extra effort.
It's really easy to do, loosen up the front bearing on your spindle, move the tire around until it falls down and stops. Add your weight to the top of the rim until the tire does not move anywhere you stop it. I use stick on weights, just keep adding until you have enough. If you don't have disc brakes, try to keep the stick on weight in the middle of the rim. This balances both static and dynamically.