I just bought a tr3 7.5' in Nov. Partner got a 3.5' for our 4100's.
used it on gravel drive & worked well. also on a dirt lane and just took a while to get used to.
I have rarely used a box blade and also rarely use a tiller.
the contractors around here do finish grading with a dozer. or a big skid loader. but just with a bucket. they dont do to well getting water away from house.
that in my opinion if not a real good finish grade.
before my combo plane on 90xt I used a ripper on back of tractor.
up untill last fall we pulled into a lawn with the 90xt, combo plane, a 4110, pulverizer & a brillion. depending on the size may have took a fert spreader.
this year will be trying the tr3.
I like the harley but when you think about building a house how much do they drive heavy equipment on the lawn. cement trucks, dump trucks, & delivery vehicles plus a extenda forklift.
compaction, compaction, compaction.
you have to go deeper than the top 3 inches to get good root growth.
I would grade with the combo plain & when done grading would drop the scarifier teeth 4-6" in the ground.
all the while I am running the comboplane, partner is running the 4100 around with pulverizer on it or working around house or small items.
we could do (actually did) a 20,000 sq ft lawn in 5 hrs, that is grading & seeding. this may seem like alot but this was the 2nd go around for this homeowner as the first guy did not do so well. we had to pull of all the old dead weeds & grass also. we timed this one and it was the last one we did for the year.
I just cant see a box blade or tiller working & having tryed them I have found better items to use.
If we take a bigger tractor,we will take along a 8' field cultivator also to use.
In my opinion a tiller is for tilling gardens although it does work well or much better to break stuff up after the field cult is run over everything.
I do not no if what we do is perfect but it does work for us & we get down in the ground. that is why a farmer deep rips his ground.
this is long enough now so make your replys and I will see what I can add.