First put a different tach in it cause the stocker's are usually inaccurate.
Second, to accelerate the car the quickest, you want to shift such that the rpm drops back to the peak torque range with each shift. Because of the transmission gear ratios, that means the shift point will actually be slightly different for each shift.
A stock 5.0 probably makes peak torque around 3600-3800 rpm; peak HP from 4500-4700 rpm. Using the gear ratios in the stock T5, that means a 1st to 2nd shift around 52-5300 rpm, a second to 3rd shift around 5000, and 3rd to 4th shift around 4800 rpm.