Quickly I just wanted to mention that the 50" Everything Attachments Grapple is only rated to 35 HP, I'm at 38 and I have done the implement rated for less HP than I had before in my life and the results weren't pretty. So I'm a bit reluctant on that and will have to do a bit more research. Last thing I want it to start paying for repairs or void a warrenty.
I sure can understand about needing to make sure it will be covered under warranty and keeping the wife happy. You certainly wouldn't want something to happen and have in NOT be covered.
I am in 100% agreement with you regarding heavy duty vs. lighter duty implements. I can certainly see your hesitation to go with a "light duty" grapple, I was the same exact way when I bought mine, and almost purchased a heavy duty model. That is, until actually operating one. A freind of mine has a heavy duty root rake style grapple on his slightly smaller tractor than mine (about the same size as yours). I loaded some logs, raked through some dirt, picked up a few piles, and did some general "playing" with the grapple/tractor. I felt that the grapple was way too heavy on that tractor, perhaps I just wasn't used to it, but it seemed like there was a full load on the loader even when empty. I bet that grapple weighed close to 800lbs.
After using that, I spoke for quite a while with Nelson Long (WR Long) and he convinced me that the lighter duty model will be 100% correct for my needs. I'm glad I went the grapple I did.
I would urge you to at least give the w.R. long a really good look. It is more expensive than the E.A. model, but you've already mentioned you don't mind paying for the right tools (I'm the same way, money isn't my first and most important aspect in the decision-and no I'm not rich) im confident that the WR Long 4' model would do everything you ask of it, and then some, I can't say that about the EA grapple.
If you decide to get a heavy duty model, look up (shoot, can't think of his name right now). There is a guy on here with a bigger tractor than you, and he bought a 72" heavy duty grapple. It does what he wants but he admits it's too big/heavy for his tractor. I'll try to find his forum name.
Take a look at the implements in my signature. With the exception with my landscape rake (came with the tractor and I don't like it) every implement I use is very heavy duty (and not just because the marketing department named it "heavy duty"). I don't bother with light duty implements, they are a waste of money and time. Fortunately, I can say that grapples seem to be a little "under" rated if anything. It's not the same as 3 point hitch implements.