The last time I moved tree branches with my tractor, the forks sorta helped by carrying some of them. But I knew that being able to clamp them down would be a big improvement. But the cost of a true grapple just didn't make sense for the occasional use that they would get. So I took a chance that the 'Thumb' offered by Greens-Machine.com would give me what I wanted. The project of removing a couple of trees on our property gave me the excuse that I needed to move beyond just thinking about it.
The Greens-Machine website really focuses on mounting their thumb onto buckets. And I'm sure that it works well for improving the usefulness of buckets. But I felt that using their thumb with forks would offer more capacity and easier manipulation of the load, as well as better visibility.
My forks are different than most, since they were fabricated by a local welding shop. So my installation was extremely simple. I just drilled 4 holes in the upper box section frame of the forks and bolted the base of the thumb to it. I already had 2 x 1/4" hoses set up for angling the loader-mounted snow plow, so I used those hoses which run from the rear hydraulic outlets to the front. (The photos show the hoses in a very temporary routing setup). Although Greens-Machines' kit includes a couple of orifices, I found that I didn't need to use them; the open and close speed are about right.
I've only used the thumb once, and it worked great.
Here are some photos.