Yea, the ideal shift point (where you maximize torque on the wheels) would be much higher than 6000 rpm. To find that point, you first need to know the drop in rpm that you get when you change gears; this will be different for each gear change. Once you know that drop, look at your dyno graph, look at the rpm you'll you think you want to shift at in your lower gear, and take note of the horsepower at that rpm. Then, go down the graph by the rpm you figured up earlier, and look at the horsepower at that rpm (where your motor falls back to when you shift). Under ideal conditions, you want these to horsepower numbers to be the same, so that just as the horsepower is dropping off in your lower gear, you change gears to drop the rpm to the point where it's picking back up again.
So for example, looking at your graph, and only going by how far your tuner pulled it out, the ideal shift point would be around 6200 rpm, where it's making about 495 rwhp. On a T3650 transmission, the drop between 1st and 2nd at that rpm would be about 2500 rpm. So we go back to 3700 rpm (where your pull will start again in 2nd gear), and see that it's only making about 325 rwhp at this point. This is certainly not ideal, and in real life, I bet you'd feel a noticeable dropoff when shifting from 1st to 2nd gear.
But let's say you do wind it out to 7000+ rpm. At 7000 rpm, the horsepower has dropped back down to 380 rwhp. You follow the rpm drop between gears back to 4500 rpm, and find it to be 380 rwhp. And bam, there is your ideal shift point.
Of course, this is assuming your valvetrain and drivetrain can handle the rpm, but even with your wide power curve from the positive displacement blower, you can easily see why the Trickflows love to turn some rpm.
