Gday Mikizee and welcome to CS.
1. Grind where the grind is correct for you. Forget what any manual says. Every grinder is different - if you got another EMO480 you would find you need a different grind setting again, just to get the same pour as youre getting now. If you get too close to 0 to get an espresso pour I think you can order some shims from Sunbeam to make the grind setting back toward the middle of the adjustment whilst still grinding espresso fine.
2. Dont know much about the guage as I dont own a 6910, but you will find espresso to be a dark art. It is difficult to replicate shots until you have quite a bit of experience under your belt. Focus on pinning in an exact technique which you can replicate perfectly every time - once you can get close to this you will find that the grind setting is all you need to change to speed/slow pours (and Im assuming get the guage in the same spot each time)
3. Everyones a little different but we generally advise to aim for a 25-30 sec extraction of 60mL using the double basket to begin with - and then start tweaking from there to suit your tastes. Start timing from when you hit the button.
4. Yes you want to stop the pour when it blondes. But you also want to get at least close to 60mL using the double before it blondes. If its blonding prior to this, you might be getting channeling in the puck, underdosing, or beans may be getting a little old.
You seem to have a good grip of the basics you need so far - it will come down to practice, practice, practice. Make sure you devise a routine which you can replicate perfectly every time (i.e. dose, distribution, tamp). If you are playing with one of those variables - make sure it is only one at a time so you can tell what difference that one change made. In the end you want to be able to replicate the technique exactly every time so all you need to change is grind to get to where you want to be on your pour.
Good luck and enjoy!