- keep best grid as fall back option like W1
After actually writing code for this, I came to the conclusion that it doesn't make sense.
If it matters, this is an indication that something's wrong in the integration. If it doesn't matter, we don't care. In any case, the last grid will be updated before being used in the final integration pass. And in this integration pass, the grids are not updated anymore in the default setup. This was different previously, and there was also the bug that rendered the reported error too small.
So, using the 'best grid' gives a false sense of security. Furthermore, it takes disk space, which might matter for some use cases. I'll push this to the obsolete list.
