We are remodeling our pool (new True Blue quartz, new coping and tiles. Pool is 20 yrs old. During remodel, we would like to add Baja Shelf. I have conflicting info. One company says new Baja shelf must be built first and cure for three weeks before it will be ready to be replastered with Quartz material like rest of pool. Another company told me the shelf can be built during other construction and resurfaced same time as rest of pool. Which is correct?