+1 Greway. I find it easier to barre that chord with my index finger, it's the path of least resistance. Also, it allows your other 3 fingers to do other things. If you are trying to get through a song and can't quite make the voicing yet, just hit the open A string--at least you'll hit the root of the chord, and leave a nice bass note. Hitting the tone in time is the most important accomplishment. Invest and sleep with a metronome.