And I haven't graduated to cones of thread yet.
If you are using the cross wound spools of King Tut they should still be used on an upright spool holder just like a cone. If used on the horizontal pin holder the thread will come off sort of spiral like (twisted) and could still cause thread problems.
Just because the machine at the shop worked with the thread tension on Auto, that does not mean that yours will.
Remember that you are the Master of your Machine, don't let it get the best of you! You will prevail!!!