A great time to frost seed is around Feb. Catch a light snow and put it out right before a warm up. The melting snow will "suck" the seed into the ground.
Be warned about clover plots. They require a lot of work with spraying and several mowings throughout the year to prevent weed competition. I tried a clover plot this year on my property in Vinton and due to the distance, I could not maintain the clover like I wanted. Now I am doing all fall plots because they require less work. Since I live 90 min away, it's hard for me to get down there every month and mow. My fall plots I spray, till, plant, drag and pray for rain. I can do everything, except the spraying, in one day. Plus, since I am planting in the fall, the weeds do not take over as much.
This year I plan on trying shot plot in my lower plot that receives a lot of sun and has a higher ph and winter rye on my gasline plot that gets a lot of shade.