Frost seeding works best for me on pastures. I use a regular seed spreader called "Seed Easy". made for grass seed, up to Cereal Rye sized seed. It holds around 25 lb. of seed. You can do an image search, and I'm sure numerous pictures will show up. It can be used on any tractor with a PTO shaft, just bolts to the drawbar. You use a piece of straight radiator hose for a PTO shaft. I'd have posted a picture, but when I tried, it said the file was too large.
Frost seeding is done in the early Spring, last 2 weeks of Feb., first 2 weeks of March when the ground is going through the freeze/thaw cycles. The ground honeycombs when it freezes, then mellows down when it thaws, and pulls the seed in covering it. You're basically mimicking Mother Nature. Do a search for Frost Seeding, you should get many hits for it. It's a really simple procedure, just need to figure out what time of year is right for you.
It works well in the hayfield too, but you have to plan several months ahead. I run the disk over it in Nov. during a dry spell to open the surface a bit. Then come Feb./Mar. I seed it. Works very well if it gets cold enough to honeycomb the dirt.
For cover cropping, disk it up, spread seed, then disk with the disc set to a minimal cut to cover seed in early Fall, or for Summer cover crop whenever is right for your location. I also pull a cultipacker behind the disk to press the seed in.
You may want to experiment with the setting on that spreader, it doesn't have to be very wide of an opening for the seed to come out. With the price of seed, hate to see you make one pass across the field, look back, and the spreader is empty. Tried to explain that to an ex-GF 20 years some ago, but she knew what she was doing. And hour later she called sobbing that she'd spread that 50 lb. bag of expensive grass seed in about 100 feet. Gotta' admit, it was a pretty healthy stand of grass.