Here is what I can tell you from the plans:
Front End Loader Specifications
est. cost to build $ 1200 (12-3-13)
weight: 325 pounds
lift capacity: well over 500 pounds
lift height to level bucket: 73 inches
bucket width: 42 to 54 inches
bucket capacity: .21 to .27 cubic yards
bucket roll down: 50 degrees at maximum lift
built in oil reservoir
spin on oil strainer element
joystick control option
Micro Hoe Specifications
est. cost to build $ 1700 (12-3-13)
weight: 350 pounds
digging depth: 5-1/2 feet
reach: 8 feet
hydraulic stabilizer spread: 7-1/2 feet
boom swing: 170 degrees
bucket width: 10 inches
built in oil reservoir
spin on oil strainer element
proportioned hydraulics for simultaneous cylinder movements without a pressure drop
Here is what I can tell you from experience. Years ago I had tractor outfitted this way. Bigger tractor but still... When lifting with the bucket, the seat of my pants told me when the rear end was getting too light and so dump some of the load. I had the rear wheels off the ground a couple of times. Doesn't taken long to learn!
Now applying these limits to MY tractor is your question. I don't know, except that my tractor is more robust than the tractor these were first built for. And that bunches of the them have been successfully built over the last 13 years. Will I break it? Possibly, but I doubt it. But if I do, I am the one who will have built it and so no one else is better prepared to fix it. Will I break the tractor? Also possible, but I think the devises would give first. We shall what we shall see.
For the more curious, see
http://www.loaderplans.com/
And to Rob, didn't get a mower deck. Didn't want one. Don't need one. No lawn on my lot! If I need a mower (or a snow blower), I have clearly missed the mark!