Gezze looks like you used pretty much the same valve I did for my setup on my 2320. I used mine for aux hyd out the back to run a hyd top link and turn the chute on my blower. I used all custom made rubber lines and in the end was out over $800.00. Heck up here I paid almost $300.00 just for the electric diverter valve. I think I will take some of you ideas and redo the lines to hard lines as I want to add another function to the unit for a hyd side link. Gotta say your install looks pretty sweet.Dive in! As long as you can post pictures I'm sure we can help you work through any snags you run into. I'm by no means a metal master, the grapple was one of my first major projects and I leaned alot of thinks that I would do differently if I were to do it again.
However I can tell you the grapple has been one of my most used implements on the tractor, I'd say its been on the loader just as much or more than the materials bucket.
You already have the PB on the tractor for the backhoe so I'd say tying in shouldn't be a problem. That was the hardest part for my 3rd function intall, tying in and finding a place to mount the valve itself lol.
Here is the thread I did on my install, just rear remotes instead of extras on the front.