I would be perfectly pleased with those stripes! The first 4 pics the grass dosn't appear to be fertilized much, or at all. the darker green and more "lush" the grass is, the better it tends to show the stripe.
I'll ask the question first... What mower are you running? stripe kit? what kind of blades? HaHa, beat someone else to it!
I had to take some pictures of my own yard. I cut mine at 3 1/2 and if i do say so myself it looks good, seeing how i never had to fertilize it. Heres why i have not fertilize for the last two years. A Fertilizing Co. has fertilized my yard for free seeing how they keep getting the wrong address, they hang a bill on my door, and i take to my neighbor.