When spraying Atrazine, do I need to scalp my lawn first?

I usually use granulated weed & feed, which works decently for me despite everyone's hate for it, but this year I'd like to finally use the atrazine I hear so much about.

I don't usually spray my yard except for spot spraying weeds already growing so I'm unfamiliar with how to use this. Am I scalping my yard in order for the spray to contact the soil or is it ok just simply contacting the grass surfaces? Seems that wouldn't work but I could be wrong.

My problem is if it needs to contact the soil, which I suspect it does if I'm looking to kill weed seeds not germinated yet, the sprayer I have sprays so fine that it'll never make its way down to the soil. I'm thinking of getting something similar to this pic and if anyone could provide insight to if this would work or if there's somethign better I should be doing, please let me know.

Thanks