The main parting line of the mold is to be in the "Z" direction, or your calculations will be wrong. The "X" and "Y" location is not important for the simulation.
How do you know if the part is in the correct position?
If the orientation is incorrect, the clamp force required to keep the mold closed under injection pressure will also be incorrect.
The part needs to be oriented as follows
The main parting line of the mold ( open and close ) is in the "Z" direction.
This is the same for both Horizontal and Vertical molding machines.
The direction of the platens coming together determines the "Z" direction.