Jeepinator:
The box blade is attached to the tractor with the 3 point hitch. Point 1 & 2 are down low and level with each other. The third point is up high and centered between 1 and 2. The "rockshaft" raises and lowers points 1 and 2, while point 3 pivots. The length of the arm running from the tractor to the implement on the third point (commonly referred to as the "toplink") controls the angle of the implement in relation to the ground and the tractor. If you shorten the toplink, a box blade will bite deeper into the ground. If you lengthen it, it will sort of slide across the existing grade. You can do this with the toplink that comes with the tractor, but it requires you to stop, get off, unlock a jam nut, make the adjustment, relock the jam nut, get back on, start the tractor, run for a few feet, realize you over-adjusted, stop the tractor, get off, unlock the jam nut.....I think you're getting the idea. A hydraulic toplink makes fine adjustments to the angle of the box blade quite easy. The adjustments are done from the seat of the tractor, while the implement is in use. For example: You've got a little hump you want to cut off and shortly thereafter a depression to fill. Driving over the hump you shorten the toplink, the box blade and rippers bite in, cut the hump off, and fill the box with soil. As you approach the depression you start feathering the toplink back out to start depositing the collected soil.
Some other random thoughts in response to this thread:
"Final Grade" and "Cat" (as in dozer) do not belong in the same sentence. If you really do need a dozer, you have some really rough ground, but even then, it will only do the "broad strokes". You're on the right train of thought with your tractor selection for the final grading and seed bed preparation.
If your property is rocky, the earlier mentioned "Harley Rake" or a "Preparator" are great rental implements for lawn creation. If not, a box blade and a landscape rake will get the job done. I just did about an acre of yard this past summer with a Preparator (rented for a week) followed by hours and hours of work with the box blade and landscape rake.
Good luck, and have fun. It sort of sounds like I am about 10 months ahead of where you are right now in terms of "estate" ownership.