Handlebar center width

[1baddoggy]

Hello all.  I've been looking at putting some different bars on my Bolt.  I measured the stock risers at about 5 1/4" outside to outside.  My question is, what center width bars should I be looking for?  I see many advertised with 6" center width, but I don't know if they're measuring before the curve, or the center point of the curve.  Also, how wide is too wide?  I see some with a center width of 11" or 12".  That's got to be too wide, right?

Thanks!