Add 3rd function to Swinger articulating loader?

[Loaderman22]

I have a mid 70's Swinger 200 loader, it has come in quite handy around the property, but I am thinking it would be even more handy if it had a grapple. On the "dash" there is a 3rd cut out for a 3rd lever, so this must have been an option when new. One lever works arms, the other tilts bucket. The problem is, I really don't know much about hydraulics so I don't even know where to start. Maybe I should post in the hydraulics threads? I have heard/seen some guys add some sort of electrically switched unit to divert fluid to the 3rd function, but no one really shows the parts or how they did it. I have been looking at websites like Prince but it seems most are geared towards tractors where the valve body sits out in the open, whereas this one the valve is tucked up under the dash, and it would be ideal to keep it that way. I have no idea what kind of GPM this machine puts out, so I 'm afraid the grapple movement will be too slow if I get the wrong valve.