Jerry, I have tried it on firewood and it works well. You can get a good load and it stays with you as you ramble across the terrain. In fact, that is how I bent the grapple tines on my first test run. Firewood got in between the bucket and tines at different angles and as the grapple closed the tines bent to the side.
Farmboy, the specs on this bucket will serve you well. I don't recommend going any lighter with any steel dimensions.
Also worth noting, I left my grapples in 10" on each side (they are 15" wide overall), this allows you to add some expanded metal and make a step. I find myself stepping off to the side rather than down the middle when the bucket is full. Also, it makes a perfect step onto my tracks when I put my chainsaw on top the cab. Hope this info is useful.
Now I got to get to my treestand, bowhunting opened today!