Alfalfa Seed Recommendations

Newbie here,

I'm going to be seeding 300 acres of new crop alfalfa next fall.  The land is currently a very old stand of alfalfa and I believe brome grass.  Probably only 10-15 percent alfalfa left in the stand.  I'm going to take this years crop off and then burn it all down with roundup and once it's safe till it up and seed new alfalfa.  I've never raised alfalfa in ND before.  Only southern MN.  I'm totally unfamiliar with the seed available now.  This soil is a pretty hard soil.  I would classify it as silty loam.  There are some areas of gravel under the top soil however.  I have read a couple studies from the Univ. of ND research dept.  The studies showed that 8lbs per acre yielded their best results vs. all other seed rates up to 28 lbs I believe and as low as 5 lbs.  So 8lb seems to be the magic number.  What I'm concerned with is the actual seed.  Hay growers here on unirrigated land generally take one cutting.  But they let the alfalfa go way past the full bloom stage.  Don't bale tell into august.  I think two cuttings is certainly possible taking the alfalfa at bud or up to 10% bloom.  So any thoughts on that would be great.  My biggest concern is what would be the best seed to go with in a colder growing region that gets a modest amount of rainfall and in that type of soil. 

Alfalfa Seed Recommendations