I just started using the CountryLine Brush Hog from Tractor Supply and made by King Kutter.
It is a 5 foot model, with a HP requirement of 25 to 45 HP.
I have mine mounted to the back of a Max 28, 28 HP, 23 hp PTO, and it works great running at 540 rpm at the PTO.
I am not sure of a 3510, I assume it is a 35 hp Tractor, so I am thinking this thing would work great for you if the width is correct but they sell 6 and I think 7 foot units.
I have cut everything from grass to saplings up to 1", (not too many of those), I don't go over that size, since this unit should be on a little larger tractor.
My 28 HP Tractor doesn't bog-down, the 3-Point Hitch lifts it without a problem, and it doesn't over weigh the rear causing steering problems.
So far, and it is the first year, this CountryLine/King Kutter Unit is a good light to Medium duty cutter and I am thinking it should last me for a long while; now my Tractor, who knows.