I haven't planted any for quite a few years, but we have the same kind of ground and we always had the best luck with an endgate seeder or broadcaster and then harrow a bunch. I think the harrow packed the ground and thats why it worked so good.
Best cover crop we ever had work was weeds and not haying it the first year.
Alfalfa likes real firm ground the experts all say.
John Johnson, the pedigree man at so many horse sales, used to be our banker and told of when he was a little boy and his dad had the ground ready to seed and it went to raining. To wet for tractors so he had the boys ride two to a horse, one in front steering and the other in back with a hand broadcaster. He said the horse tracks all came up first and you could tell where they rode. Claimed that they got a good stand.
Seems like rain really improves the chances of a good crop of alfalfa, on the first year!