6.8 controller is famous for shorting out with the glow plugs still on. I'd go with the 7.3.
IF I was going to go with a controller, that is. Manual control is a lot better...
Modern controllers probably solve that problem. They are entirely electronically controlled, unlike the original that were mechanical with a big solenoid type thing on them. They cost a lot more than a momentary switch and a roll of 14 gauge wire though. But if you prefer automatic glow plugs, it's probably a good option if you can afford it.
You must be registered for see images attach