IIRC the pump from a 1984 TD car would not have a provision to increase the RPM when the cold start lever is pulled, only the timing advance is increased.
I just rest my foot on the accelerator to raise the RPM a bit if it's really cold, just about 10 seconds of doing this is usually enough to get it idling nicely.
It doesn't seem like a big deal to me but I do know that FIATs and I think other Italian cars had a knob on the dash you could pull to open the throttle more. I have thought about getting one from one of my FIAT sources and fitting it to my VW. It's just a cable that connects to the accelerator pedal so something like this, or even a lawnmower part could probably be adapted to the car letting you raise the idle without having to sit there with your foot on the pedal. Just don't attempt to use some contraption like this for cruise control.