Think in terms of using seed that is more similar in size.  Maybe pull out the oats, and substitute in a couple of lbs of sorghum-sundangras, or just plain sudangrass.  I don't know about millet seed size. Investigate that.  see if that would make a better seed mix. 

I saw the 5 lbs of radish, and I thought that sounds too high.  Maybe back that down to 1 or 2 lb/acre, and sub in another type of crop.

I realize you are going to soybeans next year. Still, I think I might include a couple of lbs of a clover.  Maybe not crimson, but maybe another one. I have read about Berseem Clover and Balsam clover.  If my memory is correct, Balsam clover is an annual.  Look into it.  That might be something to consider. At a couple of lbs/acre.

With the clovers and rape, I would be concerned about using 2,4-D at planting.