Yeah, I looked at the ones you are using. The tops are too loose in the middle without the straps you mentioned. The top's on the hefties are super stiff. I have used them as stand alones and my racks are designed around them. The smaller ones make great tubs for smaller or young males and they are the same height as the bigger ones, so my racks can hold two of the 40's or three of the smaller ones in a row.