Anybody replaced manual thumb with a hydraulic one on a NH or similiar backhoe ?

[Dave1953]

My new 935 GBH backhoe came with a manual thumb. I would like to convert it to a hydraulic one. There are access ports on the side of the pedestal just to the right of the BH control valve where you can tap into the hyd. system and it looks to me to be a simple job of mounting a cylinder on the thumb and bolt on a valve to actuate the thumb on the side of the pedestal. My concern is where to get a suitable valve to get the job done. Has anyone done this conversion that could offer some assistance ? I sure would appreciate it.