1)any 8.3/ 8.4 oz cans will fit with no adjustments.
2)adjust the slider in the back to put in the doubleshots.
3) read your manual it should tell you how to adjust price.
Sooner or later they will figure out that you are ripping off costco and sams and will refuse to allow you to do so. Which btw is a fraudulant return and is against the law, same as shoplifting.
4) try turning the thermostat knob to colder, if that doesn't work, try cleaning the coil or paying someone to work on it.
If what you did yesterday still looks big, you haven't done much today.