I don't think it matters much, I would probably spray it after you've aerated. I guess to make things easier I'd aerate, seed, spray and water.

 

I wonder if / how the nitrogen in the extreme blend will promote growth in the existing grass for an overseed, since a lot of the spray will be absorbed by what's already there.

 

Thanks guys. I'll blanket spray immediately after throwing down seed. I've been reading various articles where researchers soaked certain vegetable seeds in a humic acid solution before planting and the results they had on germination were interesting. They measured germination time, %, and root lengths. Compared to the control seed soaked in saline water the humic soaked seeds outperformed in every category.