Anyone have the Valco Twin Runabout?

NJLH

I have an older model that was given to me as a hand me down. I love the stroller but I find the straps are getting tight. My girls are small 14 month olds and with their winter coats, the straps barely fit. I thought I have them on the loosest setting. Am I doing something wrong? Is there a way to adjust them? I hope to use this stroller for a few years. Thanks