The extraction looks ok, I would expected the selection of the extract method to be in mesh_buffer_cache_create_requested. But that is related to the UI.

IMO more finetune options like these (performance vs quality) is needed. By default the options are set to best performance. but if for a scene the user needs more quality it could be set. Cycles has the Properties Area -> Render Tab -> Performance panel for this, EEVEE/Workbench could perhaps have a Quality tab?

In D6614#156348, @Jeroen Bakker (jbakker) wrote:

IMO more finetune options like these (performance vs quality) is needed. By default the options are set to best performance. but if for a scene the user needs more quality it could be set. Cycles has the Properties Area -> Render Tab -> Performance panel for this, EEVEE/Workbench could perhaps have a Quality tab?

I would say that this settings affect both engines at once (and so does the hair panel BTW) so it is a bit weird to add it there. But I don't have a better solution. I will make it a scene property and expose it for both engines yes.

I didn't look at the implementation, but seems fine to have this as a scene option.

Would the other, similar, options move to the Scene tab as well? Namely the SSR Half Res Trace and Shadows High Bitdepth settings.