Anyone added a 3rd function?

I may be "underthinking" this again, but after going to both ends of the internet, I've found that adding third function hydraulics to my L2800 so I can add a grapple to the FEL is going to cost between $775 for a kit, to "about $1000" to have a dealer install said 3rd function. That looks like a lot of money for what appears to me to be basically a valve, some fittings and a couple of lengths of hose.
I heard the idea of using the rear connections, but I have a backhoe attached, which is really handy for big stumps, and takes about 30 minutes to remove or reinstall, so that's too big a pain when I'm clearing brush (including trees) from my land.
Has anyone done a "self invented" kit/installation for 3rd function on an FEL that would actually recommend a fairly ignorant wrench turner (me) to try it? Or do the smarter folks here recommend I pay the dealer to install the kit and shut up?
(I feel constrained to add that I'm getting cheap because of how much I'm going to cough up to get the grapple itself, to clear the area to build a fence to enclose the well to serve the barn to...well you get the picture.)