Congrats! Welcome to the 4110 club /forums/images/graemlins/grin.gif
You seem pretty well set up. Your box blade might not quite cover your tracks, but that shouldn't cause you too much grief for most work. I trust you did get the 410 loader, too?
As far as the middle-buster, yes it will create broad trenches for you, but probably not as deep as you may want to run your drainage pipe. I just finished up the exact same project for five downspouts running the pipe out 20-feet from the foundation (I have a wet, but fairly well-drained homesite). Three more downspouts drain to the driveway, which is another project.
I ended up digging the majority of the work by hand with a lanscaper tree/tile spade (short handle, 16" long x 6"-8" wide blade) even though I used the middle-buster to break the sod. I set the sod aside and shoveled most of the topsoil to the loader bucket and then to a remote pile. I dug most of the dry-well pits 3-4 feet deep x 3-feet wide x 53" long (gee, that's the width of my loader bucket /forums/images/graemlins/smile.gif). I filled the dry-wells with 3/4 inch drainage/septic rock after lining the pits with landscaping fabric. I laid the fabric on top of the rock and backfilled with 10-12" of topsoil, and replaced the sod. Voila...one aching back and drainage pits that will outlast my ability to use a shovel. With the sod back in place and the excess topsoil aside, you can barely tell I was even in the area. FYI, they took well over an inch of rain in a short period of time yesterday without a puddle or burp.
That's a long answer to tell you that the middle buster will get you started, but only a backhoe or a trencher will keep you in the tractor seat for most of the job. You should know that I am a bit particular because I am proud of my lawn. More importantly, I absolutely HATE having to go back and re-do a job. Especially one that involves digging /forums/images/graemlins/frown.gif