I believe 1/8 is standard, 1/16 out from straight on each side, naturally.
That’s a common happening. You’ll know anybody in a 50 mile radius by your first year of racing!
As far as tire pressures go, kinda?? Anywhere from 8-14 is typically run depending on which tires you run, but your rears should not be that high. Start with 12 all around, and work your way from there. Staggering tire pressures like that will upset the kart unless it’s in smaller amounts, 1 psi difference maximum.