Hey Matt,
The speed and rev needles just pop off with a fork under them, when you put them back on, they automatically go back to zero, if not ur gonna have to guess by eye... the temp and fuel needles are a bit stiffer but come of with a fork too.. When u go to put them back on, beware that the needles can only go on one way (don't snap the pin!)
Follow the guys instructions on how to get it all out etc. when u screw the face down, make sure its flat everywhere. I had to use superglue and some other bits to make sure it sat flat. If its not flat (like mine wasn't) the needles stick in places. Also make sure u screw the screws right in. The needles get stuck on them too.
If u have any more issues with it, PM me, i've put mine in and out atleast 10 times to get it right, i consider myself an expert now! hahaha