Screamin Green is a good bet as a brdige-type formulation--and I am thinking it would work out well in the fall--so no need for a syn fert in the fall. You are right to use spot spray, as spot spray applies about a hundred times less product per thousand sqft. Also, you might consider the low toxicity-low odor products for weed control. Triclopyr for instance needs four times less less ounces per acre--water clear--no odor--organic soybean oil carrier, much less toxic than Weed-B-Gone. Triclopyr is sometimes called Ortho Chickweed, Oxalis, Clover Killer.
Secondly, you may want to consider Quicksilver herbicide. I use about 20 drops per gallon. Toxicity is even less--about a hundred times safer than Weed B Gone.
And...for some sensitive accounts I included 10 minutes of hand weeding before each fertilizer treatment. Fine for dandelions, violets and large weeds--not so easy for clover or creeping charlie. Five minutes per thousand sqft is about right. Extra time optional at extra cost. These customers usually consented to a bit of spot spraying in the fall.