I was just given, as in free, 5 steel LP 72's. They are all US Diver, and a mix of dates around 1960. They were last hydro'ed in 1986. I have only used a single AL 80 before, so just wondering if these would make up good tanks for a set of double, once checked. I can get them checked fairly cheaply, but don't know what to do with them once they are good to go.