Starting to think about overseeding orchard grass this fall

I have cut my acreage back by almost half and bought a new GP no-till 10 footer last year in partnership with one other farmer.  So now it is time to think about over seeding and thickening up my orchard grass and mixed grass hay fields. 

 

Each year I am faced with the same dilemma-  the bare spots clearly evident after second cutting will all have the very beginnings of winter annuals by the time to over seed is here-early September.  I can't spray in the end of September as it will hurt the orchard grass seedlings, late winter-early spring broadleaf spraying is not particularly effective here and if I use a cleanup spray in late april, the chickweed and henbit have already reeked havoc. 

 

Any body solved this problem, and if so, how? 

Starting to think about overseeding orchard grass this fall