I see. If you need extreme space filling, the approach used by the Scatter device unfortunately is probably not going to scale to your needs for the reasons you identified. Allowing a higher density unfortunately won’t solve the problem, either.
What you’re trying to do might be better served by dense convolution, which is also what your other question (How to put intance directly on dot? - #2 by Stephen) is getting at. This would allow placing up to a unique instance every pixel regardless of instance scale.
This would probably be a good match to implement using the Code device and run on the GPU, although doing so is obviously not a friendly user-task, but rather coding/development work.