Mammoth or the Peredovic sunflower will come up when planting from your black oil seed bags. The Russian Mammoth every knows is the 9 footer with one huge head sunflower. The Peredovic is 5 feet with multiple medium sized heads. It depends on the source the company got seeds from previous year as to what comes up. For years I buyt 40lb bags of Agway black sunflower when they have pre winter sale. First year planting in spring remainder of bag Mammoth came up then two years in a row when planting rest of bag as border the medium multi head came up then had a year of mammoth then back to multi-head and so on. There are only two major plant sources of black oil, you'll get one or the other and random as to which each year from same company.
About the easiest thing to plant is sunflower. I remove sod or till then scatter by hand as sparse and even as possible. You'll be amazed at what a few left over pounds can cover for planting. Ideally you'd go back and thin them out so there are plants every 14-18 inches. I just hand scatter as loose a spacing as I can manage then rake it all in, water and walk away. That's the extent of it until harvest.