Hey. I'm new here and we are moving from about a year of steeped and extract brews to the all-grain. So, we've bought the Rubbermaid 10 gallon cooler. Will buy a false bottom if we have to, but really want to make one. What do I need to buy? We've measured the diameter and it looks like 13'' is the size, but when we look at websites, they only list 12'' false bottoms. As well, where could we buy perforated stainless steel - Rona, Home Depot, etc. Any advice would be welcome.