If I am reading this correctly, your pole is 19' in total length, with the base 12" in diameter and I assume it probably tapers to the top?
If your loader can pick up the total weight of the pole, take a strap and locate the approximate balance point by strapping and lifting at different points until you get close to finding the balance point. Mark this location.
You now need to rig the pole with a sling strap just above the balance point. My "guess" this point will be about 8' from the bottom of the pole. If your loader will lift to 9' high, you should be able to attach your sling strap to your loader with as little distance between the two as possible. The "key" is having more weight below your pick point then above.
Assuming the pole is tapered you might need to cut some (two) wood wedges and tape them tightly to the pole at your lift point. This will help hold the strap at the desired location. Something along a 45 degree angle should work.
Might also want to put some padding on the loader bucket to keep the scratching /marring of the post to a minimum.
I would add a few shovels of gravel to the bottom of the hole. Using a helper to guide the base of the pole, slowly lift and move pole to hole and lower. If your have good control, lifting up and dropping it a few inches will help compact the bottom of the hole. Centering the post in the hole will help to plumb the post.
To plumb the pole, again assuming it's consistently tapered, you will need to make two marks on the pole, approximately 12" apart. Measure the diameter of the pole at each location, subtract lesser from the greater, then divide that number by 2, which equals "x". Take a 12" 2x4, and at one end, measure from the side "x". Rip cut the 2x4 from nothing to your x measurement. This will replicate the taper on the post and allow you to use your level and plumb the pole. Ideally, you would make two of these, and tape them along each end of your level.
Of course, pics would have been nice. I could be way of base. Hope this helps.
