Scoop pans are wonderful things for moving a lot of dirt if your tractor is not equipped with a front end loader....like mine...I have moved hundreds of yards of material with my little 850 John Deere and once you get a rhythm going it will surprise you what you can accomplish...
But I would rather milk a porcupine than try to cut a ditch with it...
If your box blade is as wide as your wheels, you already have an excellent tool for cutting a ditch and maintaining the crown on your road....If it is larger or smaller....well...that may complicate things a bit, but try this out anyway....
Start by parking on a level surface, and raise the box to its full height....lower one side of your box blade to within about 4" or so of the ground...drop the scarifier tooth on that side as well...make sure you have clearance to drive around with the box lifted to full height without dragging that tooth on the ground...
....enter the ditch and begin the cut by dropping the blade into the dirt as deep as you can without loosing traction...the tooth will rip up the accumulated silt, the dislodged dirt will pile up in the box and naturally roll towards the gap at the high side of the blade, where it spills out creating a nice berm of loose soil at the side of the ditch.
Repeat as nessesary...
One my 1200' long driveway, which is right up against a fence, I have to raise the blade and drive all the way back to the front to make additional cuts...if you have two sided access, or are ditching both sides of the road, you can make cuts both ways.
Once you get that first cut established, your tractors wheels will settle into the ditch and help help keep you on the straight and narrow.
Don't over-do it...your ditch only has to be a few inches deep to effectively handle the run-off. It is more important that it smoothly pitches downhill, with minimal humps and bumps in the bottom to create turbulence.
My land drops 6' over the 1200 feet of driveway, and pitches gently towards the driveway, I only ditch the low side of the road and it seems to work just fine this way...even during the wettest part of the rainy season the dirt road remains passable...I have not spread gravel yet as I am waiting for our house to be finished and the heavy vehicle traffic to finish...
Once the cut has reached a depth you like, you have the problem of that berm of loose earth that will block water from reaching the ditch...so you will have to spread that dirt across the driveway to smoothly crown the road.
Tho I own a rear blade, which is ideal for spreading the dirt, I am lazy by nature, thus I have found an easier way than changing implements...I acquired a bunch of railroad cross ties a while back, so I chose the straightest and heaviest one and drilled it at each end to accept a chain.
Now after I pull up the scarifier tooth and return the blade to the 'level" position, I back up to the cross-tie and chain it across the back of the box blade, one side up close but not too tight to the box on the "ditch" side....on the other I leave about 6 feet of slack in the chain...I run the chains thru a pair of holes that are down low on the outer corners of the box so I can lift at least one end of the tie...
When I drop my wheels in the ditch and lower the box so the cross-tie drags flat on the ground but not so low the blade engages the earth, the angle the cross-tie assumes pushes the dirt towards the middle of the road.
A few passes and the dirt is smeared smoothly across the driveway and water can run accross quicly without saturating the driving surface.
Once you have moved the dirt to your satisfaction, stretch out the chains full length and smooth out any ruts caused when the end of the tie dragged along the driveway. Raise the front lip of the tie as needed and that cross-tie leaves a finish on the dirt that my yard rake has trouble matching....
I will groom my ditch just before the rainy season starts here in my part of Texas...once a year is generally enough.
Your mileage, will vary...
I hope this helps!
Be Safe Out There...
Terry