Yep, sounds like you've got a project ahead.
We've built several retaining walls with, what sounds like same sorta blocks.
Ours are 2x2x4ft. We made up this grapple. Worked good. Hanging on a chain
off the bucket of our Case 580E. Turning radius not an issue then, as you just swing
the block around. Just a thought, but you might save yourself a bundle on that telecrane, if you fab something like this up. Plus you can start working away at
it at your own pace. If you want, I can easily pull it out of the weeds, and give
you some measurements. Or, you can borrow it if you want.
It has a trip feature, which was nice, as operator
could go and get the next block alone.
It's kinda hard to see, but in the 3rd pic is a heavy angle(on the ground). That has
sarated(sp) teeth, that grip the block.