HPSDavid, I've swapped more than a few handlebars. First set the drops to where they are correct for you, then move the levers to the position you like. Some handlebars have an outward flare to the drops that will prevent the levers from being aesthetically 'correct', which should be the least of your concerns. Ride a few miles and readjust as needed. I've used a piece of string to measure from the end of the handlebar the the lever's clamp to even the levers horizontally. A stare and compare from the front to even out lateral placement.

What, Kimmo, wrote about regarding the angle of the hoods is important also. I adjust my hood's angle to work best for out of the saddle power (climbing, gap bridging, etc.).

Brad