The "Tolerance" factor is best described from the API Inventor manual - pls see below.
From my experimentation - the valid tolerance range is 0.0001 to 1. Numbers higher than 1 are treated as 1.
The tooltop reads:
Specifies the Level of Detail to load into Octane. 0.0001 = high LOD and slower load times, 1 = low LOD and very fast load times. The Inventor LOD cap is 1 (so higher numbers than this are treated as 1).
In Cinema (no matter how it is imported, whether I have 4 objects or 2400 for the same model) - it takes ~5 seconds until the render window opens.
Using the OctaneRender for C4D to load the scene into Octane is a totally different process to using the Inventor plugin - since the C4D model has already been de-instanced (so it's just a single mesh), whereas in Inventor the plugin need to convert all the part instances to meshes, which is a more complex process.
something useful that might be nice to have: make the input in the tolerance setting take '.' and ',' (point AND colon) to separate digits lower than 0. when I put 0.1 using my number pad the value is changed to 1 as the '.' is not accepted. This is only visible when entering the value, closing the settings and opening them again.
This is related to the regionalization settings you have setup for Windows. Can you post a screenshot of your Windows Region->Additional Settings window pls?
Paul