I finally got to use the new rig, even though it was only to move a load of wood to the porch from across the yard. Worked like a charm. I was able to put almost twice as much wood on the carryall as before, and loaded up the front carrier to what seemed like a reasonable capacity, just heaped up a bit but not so much I needed to strap the load in, although I might have put a strap on it if I was going farther.
I backed up to the porch and unloaded the carryall first, then turned the tractor around to unload the front carrier. I could definitely feel the difference with the weight on the front after unloading the carryall, but when it was all loaded up it felt nicely balanced.
Sorry I didn't get a picture, I'll do that next time. I also didn't measure the stack on the porch (it was a week ago so it's more than half gone). I'd guess the total load was a pile about 24-30" high and 8 feet long of firewood cut 16-20 inches long, give or take.