This brand does seem top notch and I love that it is narrow fit for those skinny low percentile babies like mine! (themonarchmommy.com)
You could squeeze a smaller friend in the middle seat if you need to, but it will be a bit tight, considering how narrow the Fit is. (thetorquereport.com)
The Womens Madrid Birko - flor Narrow Fit from Birkenstock combines a Synthetic upper with a durable Rubber sole. (kelkoo.co.uk)