My favorite rear ballast is a box blade with a few suitcase weights hanging on it. This gives me good weight, plus i have a very usable attachment ont he back.. and doesn't stick out much.
My next favority, and the one I leave more or less permanently attached to my ford 660 with front end loader is a plastic cattle feed tub filled with concrete. I made it by putting a couple barriage bolts thru the bottom of the bucket, and drilling and cutting a piece of flat bar stock to make it a toplink mount point. I set the empty container on my 11 hole drawbar, and then put nuts and lock washers on the carriage bolts on the bottom side, and ont he top side.. so ehte nuts were sandwhiching the bucket to the drawbar. I used long carriage bolts so they stuck up 6" to 8 " into the empty tub. I put a pin thru the flat stock and my tractors toplink, and wired it so that the toplink was hanging where i wanted it to be, and this made the spacing for the toplink correct with the bars.. I made it so the bars hung in a good 8" into the tub,and slightly bent the hanging ends for a good hold inthe concrete.
I then got the hose and a hoe, and 5-6 80# bags of sackcrete and just mixed in place.
Looked like this when finished. i estimate the weight of the concrete and tub, and drawbar and assorted hardware to be about 500# or so. Best part is, if i ever ditch it, I can just remove the 2 nuts and lock washers off the bottom of the drawbar, and I have my 11-hole drawbar back, and I only have to ditch the plastic tub/concrete and the few metal bits.
Cost was 3.99 a bag for the crete, the tub was 'free' as it was a cattle range 'lick' tub i had leftover. The 10" carriage bolts washers and nuts were 6$ and the 3' flat bar I used for the toplink was about 7$ from the piece steel ( short bars, flats, angles, etc ) from the hardware store. So that makes 37$ and about an hour and a half of time..mostly mixing concrete in place. Also.. the drawbar I used wasn't a standard length drawbar.. It was one of the shorter ones.. like for a BX.. 18" but was still cat 1 pins and thickness.
Works great.. and makes my 660 steer muuuuuch easier.
Soundguy
Looks like this..