Hey , I want to build a baby rack but debating whether to use the 6qt or the visions v18.The pro to the 6qt is they are like a dollar but I find them to small.The v18 are about $2.50 more for each tub ,but like that they are less in height and are 4.5 inches longer.Would like any feedback and those that have used the 6qt tubs about how big can they remain there before you have to go bigger.....