I’ve got a complex model that renders nicely in the Shape Diver viewer but is heavy enough that when you tweak the parameters its not quite clear what the result is going to yield. Its the type of design that you would want to get the center lines correct first and then turn on the rendered surfaces. Is there a way to turn off surface renderer in the view and only see the center lines to speed up the computing time AND then once about right turn on the surfaces? Appreciate the help.
Rendering in the viewer itself is not of particular concern. In the case you are describing, the issue is more when creating the surfaces in Grasshopper (which might be more computationally intensive than simply manipulating curves) as well as transferring the surfaces to the viewer, which is heavier and therefore also a time factor depending on the quality of your connection.
For these reasons, I would advise to implement the toggle you are describing directly in your Grasshopper definition. Set it to false by default to only render curves, and enable it only when you want to render the more complex geometry.