Everyone has been telling me it's best to spray 24d in the fall, when the plant is putting energy into the roots for the winter. In the spring, you may "appear" to kill the plant, but really you are just killing the foilag. And the plant will come right back because you didn't kill the root.
As to thin vs thick. Accord to label I am actually on the heavy side (least diluted.) The jug I have, iirc, says 1.5-3 pts per acre. So I use two pints. It also says in the column right next to that 20-200 gallons per acre.
So diluting 1 pt in the 15 gallon sprayer, and spraying 1/2 acre is not the middle of the road in terms of per acre, and toward the lower end of dilution.
Mixing 8 oz per gallon (12 oz per 1.5 gal)...seems strong as crap. Perhaps not a concentrated version of 24d?