Need help with these two issues !

Hey,

My Golf has the 1.8l 8v Engine code "DX"

First Question:

Does anyone know the normal resting place for the temperature gauge on the dashboard ? Mine used to run 3/4's of the way across but since I have rebuilt the entire cooling system it now runs at just over 1/4 of the way across, on the edge of the hollow white box at the start of the gauge. When in traffic it rises to the centre at which point the fan kicks in and cools it back down. I was under the impression that it might be running too cold because I might have bought the wrong thermostat which is causing it to let water into the radiator prematurely.

Second Question:

Does anyone know how to adjust the metal circular plate found inside the metering head? (Correct me if I have the wrong name for the part) It's where the injectors begin above the air filter. I stupidly fiddled with it and I think it is what is causing my car to have a slightly lumpy cold and warm start, I'm pretty sure this is the issue as adjusting it made it start better, it just seems to be extremely sensitive and I'm not sure how it is supposed to be aligned.

Kind regards,

Bill.

P.s. If you need any more information regarding these questions I can post pictures and go into more detail.