Thank you very much, Markeee,
At least we have a starting point with the file.
Yes, 1MB is the file limit; I did not think to mention it; a Primitive and a "Floor" object don't trigger that sharing. But, yes, I should have mentioned it.
Fingers crossed, you can work in the way you like.
Yes, that was my first thought; setting the Simulation Scale might help, but in my tests, I do not go that small.
All the best