My intended use is that I have a good acre of yard to rework and re-seed as it has gotten rutted up. I had also planned to use it to groom trails through the woods - but I'm not sure how it will do there given the tree roots one can encounter. We have heavy ground. I see I had not updated my profile to include a synch-shuttle JD 5055 which is what I had planned to match the tiller with. The 5055 is rated 45 HP on the PTO.
Thanks. Helps to understand the application!
Well, everyone has an opinion, and you asked for opinions . . .
For "yard" work or "lawn" preparation, I would absolutely want a tiller that covered the tractor's tire tracks. You're trying to get this as smooth as possible and reseeded. The tiller is going to fluff this up a LOT, and you'll leave deep tracks if it's not full width. Even foot prints will leave depressions after you till it.
For a lawn area, I till the area then pull a roller over it to get it compacted enough that it can be seeded. You might need a roller that's as wide as your tractor too.
On the other hand, this might be an application where you can just CARRY the tiller behind you -- don't drop it all the way down -- and just let it till the top couple inches. This is a good way of knocking down the high spots and loosening enough dirt to fill the low spots. Also doesn't create that real deep fluffy seedbed that has to be rolled.
Either way, I still think you're going to end up fighting the tire tracks left behind if you use a smaller tiller on that big tractor. Those ridges that would be acceptable in a pasture area probably won't be smooth enough for your yard.
Still curious

-- is the JD 950 4WD? I have a 30 HP tractor with a 5' tiller behind it. It does a GREAT job and would be perfect for an acre of yard. (4WD might not be necessary, but it sure helps keep the tiller from pushing mine forward when I'm creeping along.) (For trail cleanup, I might rough up the occasional trouble spot but a tiller might just make your trails muddy. I'd tend to drag a box blade around in the trail area to knock off the high spots and fill in ruts. You want the trails to be compacted.)
Good luck with it!