If you want some diversity try splitting the plot into thirds and put 1/3 to clover, 1/3 to brassicas, and 1/3 to winter wheat or rye. Seed the brassicas from now til early September, the wheat or rye in mid August to early September, and the clover in mid August to early September. Add some oats over the clover to give it some cover for this fall. The clover will take off in the spring and be good for a few years. You can rotate the brassic plot and the wheat/rye plot so you’re not planting the same thing in the same spot every year.
Regarding Buck Forage Oats and other name brand seeds… You can buy generic equivalents for a fraction of the price of the name brands that are just as effective. Public varieties of oats (Jerry, Ogle, etc) are about $15 per 50 lbs vs $35 per 50 lbs of BFO for example.