They are excellent and efficient tools for moving dirt from one spot to another. We purchased a full size? one that matched well with a full size Massey 165. I'd guess it held at least a cubic yard. First, we used it to build a dam on a nearby river, after receiving permission from local government. The first step was digging a "keyway" trench across the river valley, then filling it with good clay soil from the nearby area. Then we started building up the base of the dam while the river ran through some old deisel drums with the ends cut out. I think I'm remembering correctly that the final dimensions of the dam were 100 foot wide at the base, close to 30 feet high and around 1000 feet across total. We also used that "dam scoop" to cut the emergency spillway, then used a heavily modified back blade to level and smooth the overflow. This project ran 6 days per week, used a minimum of 2 drivers, each working a 6 hour shift, for a number of months. The finished lake is still full and visible from above, as seen in this screen shot from Google Earth. I think it was built around 1985.
Now, the reason we went to all this trouble was to end our dependence on diesel fueled generators. There was no way we could get connected to the national power grid, so all our power came from generators. For a number of years we had electricity from 6 am til noon, then no power till 5 pm, then off again around 10 pm. Diesel had to be transported from town, a good half hour away, in diesel drums, then stored in the generator house till needed. Worked well until the gas stations didn't have diesel (happened often) or had no electricity (I showed Dad how we could hook up our gas powered arcwelder/generator to the building power supply). So, with two small rivers bordering our southern property line, Dad wanted to install a hydro supply. He worked out that we could bring both rivers together to a central holding place (Fish Pond) and have enough water with enough fall to generate about 20Kw of electricity. Due to seasonal variance in the water supply, there were periods when we reduced water use so as not to run out our supply, so we only had about 10 kw on tap, but when you consider that our "big" generator was 10Kw, and ran only part time, you can see how we felt VERY fortunate. Anyway, the dam was needed to both create a reservoir for the dry season, and to raise the water about 6 feet so it could fill a supply ditch 3 feet wide that ran from the dam site down to the holding pond. The distance from the holding pond to the hydro itself was about 1200 feet. Dad calculated that the size pipe for that distance to avoid excessive water loss was too large to be economical. So, starting at the holding pond, Dad used the "dam scoop" to build a level ramp, which was then dug out to carry water in a concrete lined channel, to a point that was about 300 feet from the hydro site, but about 50 feet above that location. That allowed him to use much smaller, cheaper pipe for the final run down to the hydro.
So, effective earthmover, uncomplicated, used the tractor we had on hand and didn't need to buy complicated earthmoving equipment. If you need to build a dam or a ramp, fill low spots or carve away high spots, I'd highly recommend this attachment.
I see I did forget one point. Our scoop had no hydraulics to dump it. The scoop pivoted close to it's center, but was balanced such that when empty it would pivot back to the "scoop" position, and when full would pivot slightly forward, then you lowered the tractor arms slightly so the blade caught and would pivot open,catch, and spill it's load as you drove forward. The full size scoop cut well in all soil conditions that we encountered, and as we gained experience in its operation, it would do a good job of smoothing out it's load.
We had large skip or drag loaders like that in the Army. The hoppers held 20CY. They where pulled by a dozer. They could load and unload themselves.
My 1964 A/C B10 has an "earthcavator" attachment that can drag a hopper full of soil. It is only three feet wide. The B10 is only 9 hp. It doesn't move much at a time. I agree that a FEL is more useful and fun so, that is what I use.
Howards' project is terrific. I hope that it has worked well over the years.