Then, level the spindle by adjusting the TT’s feet until the arm does not want to move inward or outward when you "bounce" the arm as frogman mentioned.
No this is wrong - if you level the platter, and then alter the TT feet to level the ET tonearm spindle then the platter would now be out of level.
You level the platter, then level the ET using the 2 pillar screws at the base of the ET arm.

