Dear Rjinga

Thank you very much for your inquiry. You seem to have two issues, how to fix the problem and how to prevent it from happening again. First I think you are too far apart with your passes. If you see an even distribution, this can be the only answer. The material should throw from wheel to wheel of the passes. Now, how to mask the issue. Not quite as easy. I can think of two solutions, both of which involve adding fertilizer to the lawn. First, go back over the lines that have been missed, right down the middle of them, as in theory if your spacing was too far, this should fill in nicely. The second option is to fertilize the perpendicular to the original direction at the appropriate spacing. This will mask the symptoms form a color standpoint, but you may have to mow more.
From a timing standpoint, if you irrigation there should be no issue with burning your lawn if you are within label directions. You can use the weed/feed product with no issues on the turf. You can also use another fertilizer. The real issue is trying to match the amount of nitrogen you have already put down as this controls the color.

Again, thanks for the question and let me know if you have more.

Respectfully

Trey Rogers, The Briggs & Stratton Yard Doctor, YardDoctor.com