Ralph, You've been a member, and presumably a tractor owner, for a long time. So I think you'll know all this stuff, but for other readers.
1. Your tractor is 25 hp. Maximum width of box blade is likely 48". Check your owner's manual to confirm my suggestion. My tractor is 32 hp, and many times, I can only pull 60" when in 4WD.
2. Weight is your advantage with a box blade. It would be nice to know the type of steel used in manufacture, but as consumers, we're not likely to be provided that information.
3. The back of the box has two blades, one curls forward, the other curls backward. That backward blade is NOT for pushing gravel, dirt, etc. By adjusting the top link, this is used to smooth the earth's surface (or gravel), after you've worked it, and while pulling the box blade forward.