I just put up a long line of t-posts with this:
http://www.danuser.com/attachments/post-drivers/t3-driver
It comes with a plate with two holes you bolt to the side of your bucket, hook the hydraulics and it pounds the posts in, in no time and without effort at all.
That one will drive up to a 3" post.
They make big ones, called “The Hammer”, some of those have grapples to grab the posts for you right off the ground, truly one man operation those.
Some rental places have those, check around your area.
Now, I cheated, walked along with a two step stool and the manual pounder to start them.
I am so short, I didn’t reach to take the manual pounder off, that is why the stool.
Once they were all in line and straight, I went along with the driver and was pounding about two post a minute, didn’t damage or bent any of them, got them all straight.
Two people, one holding the post onto the driver, I bet you can go much faster.
That driver is very safe, the post goes in there about 5" and it has a cylinder that moves up and down a few inches, about 6 times a second, tap-tap-tap-tap-tap-tap.
it only works when a post is touching the cylinder in there and someone is holding the hydraulic lever open.
The stroke is so small it doesn’t break posts, very safe.
We will be using it to drive the 2 7/8" pipe post for the pens we are working on.
Wish you were closer, you could borrow it, if you wanted to try it.
We used to push them in with the FEL, with a long pipe, so they would not bend, but it was hard to get them straight, so we had to push them over by hand to straighten them after getting them in.
I just pounded three post a while ago where one neighbor had run into a fence with his tractor and, since we had plenty of rain lately, it was like butter going in there.
If you get to it right away, you don’t need other than the manual pounder, give that a try first.