Adjust storage empty / fill priority based on how full it is.

I would like to be able adjust the priority of a storage fill or empty setting based on how full the storage is.
That is, if a storage for slag is at 25% the setting to empty it is not urgent, but if it's full, it's potentially blocking and I'd like a higher priority. Similarly, if a storage for coal for a smelter is at 80%, the setting to fill it is not urgent, but if its empty then the smelter might stop producing and filling it becomes higher priority.
I'd suggest something like two priorities; one for the minimum setting and another for the maximum setting. The actual priority would be an integer calculated to be between the two priorities proportional to where the product level is between the minimum and maximum settings. e.g. If the storage is set to fill is set to fill to 75%, the min would be zero, and the max would be 80% and the priority is set to 9 at max and 7 at min, then I'd expect priority 9 for product levels of 50 - 75%, priority 8 for product levels of 25 - 50% and priority 7 below 25%.

Just make 2 storages in line, the first with higher priority, the later (in line) with lower. The later will be filled first and ony when fully filled the first will be filled and demanding with higher priority.

Or just set it to higher priority right away - when emptied the trucks will still head to other work anyway.