New i3V owner: A few beginner questions

[printbus]

...leveled the bed with the sheet of slightly thicker paper. Should I use something really thin?

That gap is just one of the tweaks you get to figure out. When everything else is right and coverage doesn't seem to be pretty solid on the first layer, adjust it thinner. I've read how some people eye-ball the skirt while it is being extruded and manually adjust the Z-rods as necessary to get the "squish" they want. Since they may jump in with it later, I'll point out that there are also some proponents here that recommend incorporating an autoleveling approach that turns the whole leveling and gap issue into a matter handled by firmware.