1) that 2mm (or more) you’ll need to take up the slack of the headset when you put the forks on, so might be worth adding in a 5mm (or smaller) spacer too. The top cap pulls the forks up into the bikes headtube/headset, so you need a gap underneath the cap (max of about 4-5mm?).
Remember if you remove these spacers from below your stem, your bike front end (handlebars) is gunna feel lower, might be fine, but worth mentioning
2) If you talking about this “750mm” figure, it’s rubbish, it simply can’t be/isn’t true*.
*Please no one go and prove me wrong on this, with some custom madness, for the point of this thread I’m right, ok?