Thank you for the photo.
Mine looked the same, both facing up. I went over the drive line and could find nothing in the line of dents or missing weights. Both u-joints look fine, no movement at all.
I did take the slip yoke out and reset it 180 degrees, I'll try it out tomorrow and see if that helps at all. I'm growing more and more suspicious of the rear end, I'm wondering if a ring and pinion could cause the vibration it has over 240,000 miles on it and both the axle bearings were toast.
Dave