fractional scales come too late
Looking at the fractional scale protocol, there appear to be no ordering constraints at all on when these events get sent. In practice, it seems they come too late.
What happens there is that we create a surface and its fractional scale manager. So far, we only have the monitor information, which has scale 2. Then we get a configure bounds event (which has bounds that are according to the fractional scale, 1.25 in my case) and a configure event, at which point we are doing the compute-size dance on the client-side that Sophie is trying to hook into. We only get the preferred scale event later.