If I just want it for 1 more yr I’ll use 15 lb annual ryegrass.Its cheap and comes back each cutting.
If I want it for a few more years 10 lbs annual rye with a mix of orchard grass,fescue and meadow brome.

I run it threw the big box on JD 750 drill,the “grass seed” box is to small and works better for alfalfa,clover not fluffy grass seed.

It takes a wet spring to get grasses growing inter seeding into alfalfa.If it gets dry after it germinates it will die off as the alfalfa sucks up all the moisture.