I think with moustache bars it is OK to go slightly wider than shoulder width. But even so my 22" Crosscut has a 24" long top tube making the reach the more important number for a smaller rider. Which one of your bars comes the farthest back?

On a side note. I'm 6'2" and my 22" Crosscut has a standover of about 33" depending on the tires and my 5'9" girlfriend doesn't fit my bike at all.