"There is no control for quackgrass unless you are going to use a complete vegetation killer."
Actually there is, or at least labeled for it. (Called Certainty but the label a few years ago removed cool-season grass use). Some people do use glyphosate (Roundup) for spot treatments in lawns. But yes you're right, I was forgetting we were talking about weed grasses in lawns only here!
In our "lawn" anything goes as long as it's green - for whatever reason we don't have any crabgrass in it, it was elsewhere that I've seen Dimension used on crabgrass (same active ingredient as the Bonide and Hi-Yield I think you mentioned earlier RpR). An advantage with the active ingredient, dithiopyr, is that it also has some post-emergence activity on crabgrass as long as it is at an early enough stage of growth. All it took was one well timed application a year or two ago and the crabgrass was gone and so far hasn't come back.
There's a good article on crabgrass control below. They do mention a fall application (October-November) may carry over and still work as a spring application in some trials with some products and in some areas where that was tested but seemingly not all. So where and with whatever it does work, it's not intended to be actually active in the fall, which makes much more sense.
http://turf.unl.edu/NebGuides/...
One thing to bear in mind with these selective herbicides in turf is that one needs to know what the desirable grass species are that one has growing there in case they too are susceptible to the product as well as the target weed grass.
Edited for clarity
