You will want a hitch on it. This is a darned if you do, darned if you don't thing. Have a hitch sticking out, & you will back into everything & leave an ugly mark. Don't put the hitch on, and you will miss it almost every day. If you can engineer a quich-tach or low profile hitch onto it.... now's the time.
I would not want the floppy chains, I'd want a solid top link. You can custom make a short one from the front of the barrel, but realize how that drastically changes the 3pt angles and get it right.
However, you can put 2 limiter chains from near the bottom of the barrel, up to the top link, in addition to the solid top link. Then the chains will carry the weight of the barrel, not your hydraulics. Many mowers have this type of limiter chain to keep the front of the mower from dropping too far. Know what I mean, check it out.
My uncle built one long ago for his IH 404, he intentionally put the lower pins in too low so the barrel would not scrape on the ground if the 3-point was lowered. He parked the barrel on a block of wood. Me, I would prefer the limiter chains....
Now, a person kinda gets up to rammimg speed once in a while with a loader, & you might be using this thing for a decade or more. With a 1/2 a ton back there. I'd reather have a solid shaft through the barrel, rather than a couple flimsy rebars welded onto some short ears. Consider a decade or 2 of stress.... But you might be building this part more robust than I am picturing in my head.
Some good ideas in this thread.
--->Paul