Thanks for that input Jack. I've been doing some research on this today and here's what I have discovered....
1. First, the way alltoys has his 3rd feature on his FEL is basically a diverter valve. This valve is controlled by a solenoid. Now, that's fine if all your planning on using it for is the few seconds it takes to open or close a grapple thumb. But he wants to use it for the operation of an auger. That means he will be holding in that electric solenoid for 10 minutes or more at a time while the hole is being bored. That solenoid will NOT hold up. It will burn out and pretty quickly too. And, while he's busy diverting that power to pushing down on the auger bit, the other hydraulic functions will not be operational because it's an all-on or all -off propision; not metered. That may or may not be important.
2. I looked at that rear dual spool on the back of my 4344. It has an input/pressure side feeding that spool as well as an output/low-return side. By placing a Tee fitting on these two points and running them to a separate valve, two buttons could be added to the joystick to operate the grapple; one that makes the grapple go open and one that makes it go closed. This keeps the other two functions of the FEL in service while working the grapple instead of switching/ diverting the hydraulic pressure between the tip and the grapple.
In any case, I'm in agreement that dropping my hand off the joystick to bump the grapple open or closed is the best operation of the devise and it has the added benefit of allowing me to work an attachment like an auger for several minutes at a time without burning up a solenoid. Several hydraulic techs I spoke with today all told me to NOT include any electronics to control hydraulic pressures for anything longer than a quick and short operation. They won't hold up.
I recommend to anyone considering using their tractor for any accessories to consult a hydraulic expert who will listen to what you are trying to accomplish and can advise you.