Concrete Post Caps OK But Not Usable

Following up from my previous post about creating a cap for our front porch pillars out of concrete: it worked. I unformed them last night and the concrete seems to have emerged relatively as I wanted it. But we're likely not to use what I created. Why?

First, the darn things weigh over 200 pounds. Lifting them will take three people, and actually setting them in place (above chest height) will take four.

Second, our contractor pointed out that he didn't know exactly where the support post would emerge. While we'd been smart and left a 10" hole in the center to run a post through, his point was that he didn't know if he'd need the post dead center or off center enough that the 4x6 wouldn't fit through the center hole.

Third, see the first.

At least now I know we can do it. I'll probably form the next ones in place later in the construction.