04FlippedNDropped

I have been spending countless hours trying to figure out what corrections need to be made for the correct yoke and pinion angle. I have an 04 F150 lowered 3" in the front and 6" in the back. I originally heard a humming noise between 50-55mph thinking I may have some issues with the pinion angle. Recently, it has just started doing this all the time at all speeds. I've measured the pinion angles (Front angle -3.7 / Rear angle +2.4)..
Do I need to adjust the front angle at all, or do I just need to pick up pinion shims to correct the rear angle to between -5 and -3?
Please correct me if I am wrong, but I have been reading that the front and rear need to cancel each other out. So if i could get some professional opinions that would be much appreciated! Please follow up as soon as possible, I don't want to damage my transmission. Thank you for your time!!

Derek