Hi Nate,
At 7 ft distance, I recommend keeping the speakers within +/- 15" of ear level. Assuming your ear-level is around 38" while seated (typical) - mounting them at a height of 53" off the floor or less is ideal (this keeps them within a 10 degree vertical off-axis angle). You can go as high as 60" to keep them within 15 degrees vertical, but for absolute best performance - 10 degs or less is best.
Of course, this is for flush mounting, the vertical listening angle changes if you use a bracket and angle them downwards - thus opening up many more options.
formula to calculate this is: tan(desired vertical angle) = x / distance to the speaker.
Solving for x gives you:
x= 84" (distance to the speaker) x tan (15 degs)
x (height above or below ear) = 84" x .2679 = 22.5"