Pulling a dozen takes no time with a strap and loader. We do this every year removing posts used as part of a framework for green beans in the garden. Put the wife on the tractor, pull a post, remove the strap, throw the post in the bucket, move to next post and repeat.
Regarding driving posts with a tractor, I've seen folks take a piece of pipe, weld a cap on one end, then weld it on the back side of their bucket. They then use it to push the post in the ground. I've never tried it. I don't drive enough posts in a year to fool with it.
