Joystick Control on J Deere problems

[brightontrader]

I have 2 joysticks with a switch between them, they look like very old Vetus thats as far as it goes as behind is homemade wiring setup , with 20 odd wires soldered to 3 multipin boxes....which push instructions to relays elsewhere.(The whole boat is wired this way and have been ripping out and installing commercial simpler electronics as going out on an ocean with whats there is asking for trouble as too complicated when things pack up.)

One joystick now does everything but put the gearbox in reverse while the pilot house one works fine. There are 2 actuators on the hydraulic gear box, so these are working. Ditto the actuator on the injector.

I want to get rid of this setup and install 2 joysticks that just control Engine revs and gearbox forward reverse. Any suggestions please.