Hmmmm....
I loosen the axle, adjust the adjusters til they're at the same spot on the swingarm and retighten the axle.
Then I put the bike on the lift, put my $12 glasses on, and spin the rear wheel while sighting down the chain. Then I say "That looks pretty good..." Then I take the bike off the lift, take it out for a ride, and come back home and say "Yep, that's pretty good..."
