I can't remember what width I used but when I put mustache bars on a hybrid I found that I had to angle them up a lot more than I thought I would in order to get a comfortable hand position. I also found that I didn't like them for distance because there were fewer usable hand positions than drop bars.

However I like them for commuting; it's a more upright position but with more stability and flexibility than regular flat bars, plus they look 1000% cooler than flat bars.