RE: Pump pressure setting?
Here's my plan of attack: I buy a few spare needles from horizon hobbies. I use the needle from the good unit as a master.
I make a jig from that and try shaping one of the spares to match. (As the instructions to an old Fox 40 said, regarding changing the shape of the needle "If you make a mistake you haven't damaged an expensive part.")
Today low speed needles, tomorrow the world.