The snakes are a subtool endependant item , but how do I enable the local simmetry ? I can't seem to find that option among the transform window or in the simetry window ...
adjust the brush and stroke modifiers (enable stretch, decrease the step size... play around with some options and check out the IMM tutorials on the zclassroom / online docs)
Try disabling Enable Internal Reflections in the Standard shader. As long as you have a recent Arnold, that will disable internal reflections both for mirror reflections and specular reflections.
Try enabling this before you import a xref. The transforms need to be merged before you save the scene, or they will randomly move pos when you open after.
Increase the 'Indirect Lighting Scale' of your dominant directional light. Also enable lightmass ambient occlusion to make the indirectly lit areas look less flat.
To fix the rotation issue you can usually click viewcube in the top right of the viewport(might have to enable it in Display>Heads Up Display>Viewcube). rube
You could write a script that automatically creates and destroys a grid based upon the normal of the selection you have enabled. That way you'll get arbitrary angles.
Also: There's a trial option for every unlock. Click the "unlock" button and a menu opens up. On the bottom of that menu there's a button for enabling a 30 min trial period for that unlockable.