How to still get an unrotatable block rotated. :
1. Mirror cubes + XY-plane
# Pick something like a hull cube
# Put a blue symmetry wall down (XY-plane)
# Enable "mirror cubes"
# Place the hull down and check rotations, the block on the other side of the symmetry wall should be rotated and have "BACK" as rotation.
# The other 2 symmetry ones are fine
2. Template rotation
# Put a hull cube down
# Take a template of it
# Load the template, rotate it and place it down
# Block should have been rotated.