Wayne,
We're happy to help you spend your money
Regarding the hydraulics to operate a grapple, it sounds to me like you have a "power beyond" circuit and no rear remote valves. This is just my assumption based in what I've read, and I may have missed something.
A "power beyond" function, won't give you a way to operate the grapple.
There are a few options like I mentioned before, the electric over hydraulic solenoid, the diverter, and then using an already existing valve, if you have one. You can also add one or more, and it wouldn't be too difficult to do since you already have power beyond.
There is a member on here who sells some kits and is extremely helpful and really great to work with. When you are ready, I'd recommend getting in contact with Brian, his company is Fitrite Hydraulics, and his forum name is mtnviewranch (I'm guessing he has a ranch, with a view, of possibly some mountains

)
He can certainly help you choose the right setup based on your preferences and needs. I've bought through him numerous times and have always been happy. There are other companies too, WR Long sells grapples and valve kits, very easy to install and this is the style I have. Also Everything Attachments sells both as well. They are all good.
Regarding the grapple.
I won't tell you what grapple to get, because you might have some unique needs that calls for something specific.
I had very specific uses in mind when I bought mine, I wanted a perfectly flat bottom, not curved, and I wanted something wider as I carry a lot of firewood with my grapple, so I wanted a wider one. I actually wish I got the 72" model but I would never recommend that to others unless they are doing mostly firewood and have more lift capacity. I don't believe a wider grapple will let you carry anymore brush than a narrower grapple. Don't sell the narrow ones short.
I do agree with others that (because of your loader capabilities) I would stick with a smaller grapple. If you don't have specific needs for a bigger one, or a flat bottom, I'd really look hard at that Everything Attachments 50" grapple. I'd be inclined to say just buy that one, but I don't know your real needs so I can't say that.
I'll try to let you know if I'm up that way over the next few weeks.
Wayne, if you work in the woods, I'm not kidding you, a grapple will CHANGE YOUR LIFE!
(Okay maybe a little dramatic but it's seriously amazing how much more useful your tractor becomes)