I was building a bike rack to mount my ebike inside my topper and was deciding how to bolt it in. I just happen to look in a drawer and there were some spring nuts you use with Unistrut. Super handy cause the corners are slightly rounded and they have grooves that grab the track and the spring holds it in place. It is basically a perfect fit for the utility track. Unistrut makes all sorts of things that bolt together so you might want to look at Home Depot when you are there. If nothing else these spring nuts make strong attachments. Takes a 3/8 bolt. Sorry I don't have the bag with a part number but it fits the roughly 2" square Unistrut and the generic one HD sells. They aren't cheap but maybe bolt depot has them? Amazon carries all sorts of brands and quantites.