I think you need to look at the what sort of loader work you are going to be doing in order to determine your ballast needs. With only 1180 lbs of lift capacity for the 3ph, I'm going to assume the front end loader can only lift 700 to 800 pounds max. You don't need much ballast for that. Furthermore, you don't want your 3ph ballast to be near the maximum load rating due to wear and tear on the tractor.
I think a box blade or carry all will work just fine for a Cub Cadet. We aren't talking about 100 hp tractors where the weight of a box blade would too light for ballast.
I do understand what you're saying. I've used the FEL on my CCY (which, by the way, is not listed in that CC reviews list you linked to) without anything on the rear. There have been occasions where I had to back up slowly up a slight incline near a fence and near the shop, where the rear tires spun enough that I had to engage 4WD. The bucket was only about 2/3 full of dirt each time, which got me to thinking about ballast. I've looked at box blades, and in my opinion, they're still pretty bulky and sizable for the purpose of adding weight to the rear. They may be useful in the double utility of adding weight and providing a means for grading gravel or dirt roads and leveling ground, but I have no need for the latter utility. Nor do I want to fill the rear tires, as I use this tractor quite a bit for finish mowing. Hence my queries about ballast boxes and carry-alls, and I've learned quite a bit from those of you who offered advice without any condescension. Thanks! :thumbsup: