Adding 2,4D to gly can be the touch of death. 2,4D has some residual and is more intended for boradleafs.
Scratching the soil with a pasture drag or a set of discs can wake up dormant seeds. Give it a pass or two, then a light spray of gly 2 or 3 weeks later when you plant.
Old timers would turn the soil with a plow, wait a week r two, the bury the young weed / grass seeds with a leveling pass of the discs.
Before I caved in to using herbicides, I would re disc my food plots a week or two later to kill young weed seeds. I'd spread the big seeds mixed with fertlizer, then disc, then spread the small seeds with pelletized lime. IF the soil is pretty dry and loose, I would do another disc pass, just roll it in.